Pacific Northwest Native Plant Profiles

One Tree at a Time: Caring for Young Trees

Trees breathe, like we do, but in a different way. Their leaves take in carbon dioxide, water and the sun’s energy, and turn it into sugars that feed the tree. Known as photosynthesis, the process emits vital, life-giving oxygen. Trees’ ability to removal carbon from the atmosphere — and store it in their wood — helps us mitigate the effects of climate chaos: In just one year, a mature tree can absorb half a metric ton of carbon dioxide equivalent. Trees are also essential since they remove air pollutants, prevent erosion, provide shade and wildlife habitat (when native species are grown), and offer many other benefits. And while protection of large, old trees is essential, planting new trees is crucial, and they too must be protected so they can grow to a ripe old age.

If you’ve planted, or are considering planting trees in an urban or suburban setting, here are a few things to be aware of that will help your trees grow strong and healthy, as well as potentially harmful things to avoid:

• The best time to plant trees (and most other plants) is autumn — as they are entering dormancy and as the rains begin. Following leaf drop, however, they are anything but dormant below ground and the Pacific Northwest’s wet, relatively mild winters give them a chance to produce fairly well-developed root systems before the aboveground demands of spring and summer are thrust upon them.

• When deciding which species to plant, choose trees that are locally native to provide the most benefit to wildlife. Also consider light, moisture and soil conditions, as well as topography (since certain species are better at controlling erosion than others). If the area is difficult to water, choose drought tolerant species. Also consider the amount of space you have: Don’t plant too close to property lines (I recommend at least 10 feet from property lines), paths and buildings, and check with utility companies if electric lines or gas or water lines are an issue.

• Before planting a sapling, remove any lawn or other plants (especially invasive species) in a circular area, 4 to 8 feet in diameter or out to the drip line (the circular area directly under the outer edges of the tree’s branches), whichever is larger. Dig a hole twice as wide and slightly deeper than the root system; the roots should fit into the hole without being cramped. Rough up the sides and bottom of the hole with a spade or similar tool. Trim off any dead or damaged roots and branches with clean pruning shears. For bare-rooted trees, mound a cone of soil at the base of the hole and drape the roots over it, gently untangling roots if necessary. For potted trees, massage the root ball to loosen and unfurl roots that are tightly wound; otherwise they may be difficult to establish. Note: when transporting non-bare-root trees, always support the heavy root mass from below; never lift or carry them by their stems.

• Place a straight stick across the top of the hole to help judge the depth at which to plant. Since the number a major cause of tree mortality is planting too deep, be sure to place it slightly above the level grown at the nursery. Straighten the tree, judging its posture from several angles. Replace the original, native soil around the roots until the hole is filled halfway, lightly firming to avoid large air pockets, then water. Once it’s drained, adjust the depth of the tree if necessary, and backfill with more soil, firmly tamping it down to prevent air pockets. Water again thoroughly. Apply about 3 inches of organic mulch to the area, keeping it at least 6 inches away from the trunk, but slightly thicker on the outer edge to prevent erosion. Don’t use fine bark mulch or gravel or rocks.

• When saplings are planted, they’re often staked, regardless of whether or not they need it. Staking is actually only helpful if they are planted in very windy areas, if they are bare-rooted, or if they have little root mass. Plants need to experience movement — just as we do — to become strong and healthy, and improper staking can cause irreversible damage. Staked trees often have weaker trunks and less developed root systems than trees that are not staked. To test whether or not a newly planted tree needs staking, grab its trunk and move it back and forth after planting; if movement causes shifting soil, stakes will stabilize it. If necessary, small trees can be supported with two 5- to 6-foot-long stakes (on either side) driven 1 to 2 feet deep (depending on soil conditions) outside the root zone. To stake a very large tree, space two to four stakes equally around the hole, placed several inches away from the root ball of a containerized plant and 2-3 feet from the trunk of bare-root trees, preferably before planting—if afterwards, stakes should be placed just outside the planting hole to prevent damage to roots. The stakes and ties should be situated perpendicular to the prevailing wind when space allows. After planting, tie the trunk loosely to the stakes, about 3 feet from the ground, with a soft tie such as twine (never use wire) in a figure-eight loop, so that the tree is not completely immobilized and can move a bit with the wind. Very small trees can be loosely tied to a single stake. Check ties periodically to be sure they’re not too tight or causing abrasion. Remove ties as soon as the tree is stable in the ground, usually within about one year.

• Immediately after planting a tree, always remove any sticks or rods that are taped to the trunk, since failing to remove them can lead to girdling, as shown in this photo. They are only meant to prevent damage to the trunk during transport; they are not meant to be taped on indefinitely.









Tree irrigation (“gator”) bags have limited benefit and often cause more problems than they’re worth! On my winter walks I often see young trees with their lower trunks covered in such plastic, and I unzip them whenever possible to allow air to reach the damp bark.

Permanent bark damage from watering bag.

The problem is this: Eventually, the plastic (or almost anything that covers a tree trunk) will lead to a moist, dark, low oxygen environment that damages the bark and allows pathogens to invade. These bags are not meant to be left on year round, especially during the rainy season, so please remove any that you have, inform neighbors, or unzip those that you see (guerrilla unzipping, anyone?) In addition, these bags are only meant to be used for about one year, since following that period a tree’s root spread will generally be directly below the drip line (the circular area located directly under the outer circumference of a tree’s branches). Most water absorption occurs by feeder roots at the drip line (or in some species, such as oaks, quite far beyond it), so watering close to the trunk does no good (the vast majority of trees do not have tap roots) and can even cause roots to grow in a circular or spiral pattern around the trunk at or beneath the soil line, which can lead to a gradual girdling or strangling the trunk. What’s the alternative? Old-fashioned watering with a hose or watering can. Researchers who looked into artificial watering devices found no evidence that watering devices benefit tree growth and health, compared to direct watering. One possible advantage of using watering devices is less surface runoff due to their slow release, but the hazards of using bags more than a year or two (at most) is not worth the risks. Bags have to be filled with a hose or watering can, so why not just use those? Doughnut-shaped devices (or “ring bags”) don’t keep bark as moist (although they can keep the base of the trunk wet), but like gator bags, they also only apply water at the base of a tree’s trunk, so should definitely not be used for more than a year or so. Here are some good tips on watering trees from OSU.

© 2025 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Red huckleberry (Vaccinium parvifolium)


Graceful, open, and vibrantly green, red huckleberry (Vaccinium parvifolium) is a quintessential Pacific Northwest native shrub. It’s not often used in garden situations, but it ought to be, considering its beauty and wildlife appeal. And unlike other native huckleberries that ripen in late summer or fall, red huckleberry typically offers dazzlingly red (and tasty) fruit in mid to late summer.

Part of the appeal of this deciduous huckleberry is its bright green, twiggy, angled branches that support smooth, oval, and equally green leaves. Flowers are small, urn-shaped and greenish-yellow, but often have a lovely pink hue. Fruit is a spherical berry high in vitamin C, which ripens to a brilliant red. At maturity, it typically reaches five to ten feet tall and nearly as wide, although it can grow larger in optimal conditions. 

Wildlife value
In late spring to early summer (depending on elevation and latitude) blossoms attract hummingbirds, native bees, and other insects. Berries are attractive to both humans and wildlife: Birds such as flickers, jays, thrushes, chickadees, towhees and bluebirds, and mammals, including deer mice, white-footed mice, raccoons, pika, ground squirrels, chipmunks, and foxes. Reportedly, the fruit is a big part of black and grizzly bears’ late summer and autumn diet. With time, this shrub may form a thicket, which provides shelter or nesting sites for small birds and mammals.

How it grows
The key to a healthy eco-garden is the choice of plants that fit your conditions and are locally native. Of course we don’t always have the exact conditions a plant requires, especially in urban situations where natural conditions have been drastically changed. Red huckleberry is a plant that will probably need some extra encouragement, but I think it’s worth the added effort. When selecting which plants will join your garden, always check on the circumstances in which it’s found in the natural world, where it’s found, and choose accordingly. 

Red huckleberry occurs naturally in the understory of moist coniferous or mixed evergreen forests, sometimes in the transition zone of wetlands or at forest edges, at low to middle elevations from southeastern Alaska and British Columbia, southward through western Washington and Oregon to central California. While it’s quite tolerant of shade (and usually grows larger in shade), it can do well in a woodland garden with some sun if it’s not drought stricken or in hot afternoon sun. Plants that get some sun, including those found in forest openings, generally appear lusher and produce more fruit if other requirements are met. It’s usually found in humus-rich soil growing on some rotting wood — often a fallen log or an old stump — so be sure to include some in very close proximity to your new plant. In a nutshell, it needs mostly shady sites (with perhaps some morning sun or dappled sunlight) and moist — but somewhat well drained — acidic soil (pH 4.5 – 6) that has plenty of organic matter, as well as some rotting wood to grow on.

Try it at home
A few autumns ago, I added a gallon-sized individual to a backyard bed situated to the north of some large native conifers, which provide some shade. My slightly acidic soil had been amended with organic matter over the years and allowed to accumulate natural plant debris, and I added what will really help its survival: Rotting downed wood to latch onto. I finished off my planting with a layer of leaf compost, topped by a few handfuls of conifer needles and cones blown down from nearby trees, all of which help retain moisture and keep pH on the acidic side. I water it deeply but infrequently during dry periods. One last tip: Vaccinium species don’t do well with root disturbance, so don’t dig in the soil near its roots or attempt to move it after it’s been in the ground for more than a year or so.

At planting time, provide red huckleberry with a growing medium of decaying stumps or logs to mimic natural conditions.

Grab a partner
In coastal forests, red huckleberry is commonly associated with plants such as mature western hemlock (Tsuga heterophylla) and sitka spruce (Picea sitchensis), black huckleberry (Vaccinium membranaceum), oval leaf huckleberry (V. ovalifolium), salmonberry (Rubus spectablis), thimbleberry (R. parviflorus), trailing blackberry (R. ursinus), strawberry bramble (R. pedatus), salal (Gaultheria shallon), Cascade Oregon grape (Mahonia nervosa), bunchberry (Cornus unalaschkensis), lady fern (Athyrium filix-femina), oak fern (Gymnocarpium spp.), and woodland strawberry (Frageria vesca). In southwestern Oregon and northern California, Pinemat manzanita (Arctostaphylos nevadensis), California coffeeberry (Rhamnus california), baldhip rose (Rosa gymnocarpa), California laurel (Umbellularia californica), boxleaf silktassel (Garrya buxifolia), and huckleberry oak (Quercus vaccinifolia) are often associated. In the western Cascades below 5,000 feet, it’s found with mature western hemlock (Tsuga heterophylla), western redcedar (Thuja plicata) and Douglas-fir (Pseudotsuga menziesii), as well as vine maple (Acer circinatum), salal (Gaultheria shallon), salmonberry (Rubus spectabilis), Cascade Oregon grape (Mahonia nervosa), sword fern (Polystichum munitum), deer fern (Blechnum spicant), fairy bells (Prosartes spp.), bleeding heart (Dicentra formosa), foamflower (Tiarella trifoliata), and many others.

 © 2023 Eileen M. Stark

Posted on by Eileen Stark

Can We Save Oregon Ash Trees?

By now you’ve likely heard that identification of the dreaded emerald ash borer (EAB) has been confirmed in Washington County, Oregon. The Oregon Department of Agriculture believes that the infestation has been in that county for at least three to five years. The outlook is grim.

Of northeastern Asian origin, the EAB is a small green beetle in the Buprestidae family which feeds on members of the olive family (Oleaceae), especially ash trees (Fraxinus species). Adults feed on leaves and females lay their eggs in bark crevices. Eggs hatch in seven to ten days and larvae burrow through bark to living tissues where they feed, eventually cutting off the flow of water and nutrients, which causes a slow death. Adults emerge in one to two years and typically travel only about a half mile afterwards.

In its native range, this beetle is typically not found in high numbers and does not cause significant damage to native trees. However, outside its native range it is extremely destructive to trees indigenous to North America or Europe.

The EAB is now considered to be the most destructive forest insect to ever invade North America. First detected in Michigan in 2002, it has spread through much of the U.S. (36 states and the District of Columbia). Though harmless to people and other animals, it has proven deadly to all ash species in North America, including the native Oregon ash (Fraxinus latifolia), naturally found west of the Cascades in southern British Columbia, Washington, Oregon, and northwestern California, as well as central California and the Sierra Nevada.

Spread throughout the country has been mainly by the movement of infested firewood, logs, chips, and nursery stock. Movement of emerald ash borers and their host material has been, until recently, regulated by the USDA under a federal domestic quarantine. The quarantine for emerald ash borer was repealed in January 2021.

The Oregon ash tree is currently relatively common and is a significant component of riparian forests; it is the only native ash tree in the Pacific Northwest. It is widely used for stream restoration due to its wide and spreading root system that stabilizes soil, controls sediment, and moderates stream temperatures. Widespread loss of these beautiful, long-lived trees will affect water quality (including higher stream temperatures) and change the wildlife species composition of their ecosystems, causing harmful effects on species dependent on those ecosystems.

How to help
Learn now to identify ash trees and trees that resemble them here.

If you have ash trees or know of some, familiarize yourself with the basic signs and symptoms of emerald ash borer. Reports may be made at https://oregoninvasiveshotline.org/reports/create

Also check out this article. Robert Haight, a Forest Service researcher in St. Paul, Minn., proposes a strategic approach which involves identifying beetle-infested ash trees before they show signs of damage. “One way, he says, involves searching for woodpeckers. The emerald ash borer hides its eggs in bark crevices and tunnels deeply within trees — invisible to humans, but not to woodpeckers. They pick at the tree’s bark, searching for tasty grubs.” So please keep an eye out for our friends, the woodpeckers, foraging on Oregon ash trees.

UPDATE February 2023: The Oregon Department of Forestry has collected 900,000 Oregon ash seeds; it hopes to find trees resistant to the borer in that collection. Read about it here.

More info and brochures: https://www.oregon.gov/oda/programs/IPPM/SurveyTreatment/Pages/EmeraldAshBorer.aspx

Oregon’s Readiness and Response Plan: https://static1.squarespace.com/static/58740d57579fb3b4fa5ce66f/t/60772a17647ad466155f74a7/1618422303582/March+2021_EAB.pdf

Xerces Society: https://xerces.org/blog/how-to-spot-and-slow-emerald-ash-borers-in-your-community?fbclid=IwAR0iLt9u-DQlfETCOEUMet6F86Hmr8SWWYUIb-2-4G7PrItVfgYf7JVL-Eg


© 2022 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Western maidenhair fern (Adiantum aleuticum)


It’s a drizzly Sunday in June, one that requires a couple of sweaters to keep me warm. But I can’t complain when I see so many native plants thriving, obviously in their element during this cool, damp spring—ferns, wild ginger, fairy bells, goat’s beard, vanilla leaf, and many others. Western maidenhair fern (Adiantum aleuticum), in particular, which can be found in nature basking in the mist of waterfalls, appears stunningly luxuriant right now. I watch the lush fronds of a plant in my front yard, now 20 years old and nearly three feet tall and four feet wide, move silently with the slightest breeze. “Tender and delicate, but perfect in all their details, far more than any lace work—the most elaborate leaf we have,” was the way Thoreau described ferns.

If you’re wondering about Adiantum aleuticum’s genus name, it comes from the Greek adiantos, meaning unwetted, in reference to its water repellent foliage. The species name refers to the Aleut indigenous peoples of the Aleutian Islands. Although this fern was previously known as a subspecies of Adiantum pedatum, subtle morphologic differences led to its reclassification as a separate species in the early 1990s. Also known as “five-finger fern”, the common name “maidenhair” may refer to either its glossy, dark, smooth stalks or the finely textured dark root hairs that grow from a short, stout rhizome.

How it grows
A highly textured perennial with an airy, delicate-looking structure and fine-textured deciduous foliage, Western maidenhair fern grows mainly at low to middle elevations in the shady understory of moist forests and ravines, along stream banks, in rock fissures near flowing water, and even on talus slopes. It can be found in southern Alaska and the Aleutian Islands, British Columbia, Washington, and Oregon, as well as parts of California, the Rocky Mountains, and a few disjunct populations in northeastern states and Canada.


Each dark brown or purplish-black stalk (aka petiole or stipe) grows up to 30 inches in length and forks at the top into two, from which several others emerge in a fanlike pattern. Feathery pinnae (leaflets) are made up of 15-35 fan-shaped or oblong segments (pinnules), each 10-25 mm long with jagged apical margins. Like other ferns, it reproduces via spores as light as fairy dust. Spores are produced by crescent-shaped sori on the underside of pinnules, covered by in-rolled leaf margins. They can be produced during most of the growing season, but mostly in summer. For detailed info on how ferns reproduce sexually, wander over here.

Wildlife value
Lively green foliage provides microhabitat, shelter and resting places for arthropods, amphibians, birds and other small creatures who frequent the forest floor and may in turn supply food for others. Maidenhair fern may even provide perching spots for little birds who have just left the safety of their nest and are figuring out what to do next (pictured, right)! As winter approaches, the plant deteriorates, covers the soil and eventually adds nutrients following decomposition.

Try it at home
Native ferns deserve space in our landscapes. Besides being important elements of habitat for native wildlife, they might be the best choice for shady, damp spaces that are difficult to fill. Maidenhair fern is easily grown in shaded, moist areas with soil that’s somewhat acidic, high in organic matter and drains well, so consider it in beds, borders and woodland gardens with dappled shade to full shade. In hot areas, be sure to provide enough moisture, especially before and during excessively hot periods; hot afternoon sun will scorch leaves. Space plants two to three feet apart, or intermingle them with other plants that have similar needs, allowing for a mature width of about three feet. Don’t plant crowns too deep. Reportedly, maidenhair fern is deer resistant.

Grab a partner
In the Pacific Northwest, west of the Cascades, this lovely fern will do well in the company of others in the Western hemlock/Douglas-fir plant community, including western redcedar, vine maple, trillium, sword fern, deer fern, false solomon’s seal, stream violet, western meadowrue, goat’s beard, oxalis, piggy-back plant, foam flower, wild ginger, and many others.

© 2022 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Pine (Pinus species)


Well over one hundred species of pine help support our planet, which makes the genus Pinus the largest within the conifer phylum known as Pinophyta, the woody cone-bearing plants. Found across the Northern Hemisphere, Pinus is of ancient origin, having appeared around 180 million years ago. In addition to the rich wildlife habitat, beauty, shade, fragrance, rain interception and carbon sequestration they provide, the majority of pines are drought tolerant, fire resistant and most can be extremely long-lived, with some species surviving 1,000+ years when undisturbed.

How they grow
Evergreen and resinous, pines generally grow 50–150 ft tall, although some, like ponderosa pine, can grow over 200 feet (one in southern Oregon’s Rogue River-Siskiyou National Forest towers to more than 268 feet tall!).

On adult pine trees, needle-like leaves are green and bundled in clusters called fascicles, unlike other conifers. Each fascicle can have one to seven needles, depending on the species, and assist in identification. In the Pacific Northwest west of the Cascades, there are five native pine species, a few of which can also be found at fairly high elevations east of the Cascades summit. They have either two, three, or five needles per fascicle, which stay on the plant for anywhere from two to forty years, again depending on the species.

Seed cones (female) are hard and woody, with tough scales that serve to protect the developing seeds until dispersal time comes. In some species, maturity of the cone causes scales to open and free the winged seeds. In others, scales need to be broken or pecked open by a hungry animal in order for the seeds to be released. And then there are the species that have scales sealed shut with resin: Known as “serotinous” cones, they need a trigger to release their seeds. Although serotiny can be caused in some plants by excessively moist or dry conditions, high solar heat, or death of a branch or the plant, most pines that are native to regions where wildfire naturally occurs depend on the high temperatures from periodic fire to soften the resin and expose the seeds. Fire has been a part of various natural ecosystems for millennia; having a canopy full of seeds ready to go following a fire ensures dispersal for a new generation without competition. But it can take decades for that to happen and on many sites currently, such fire regimes no longer exist. When natural fire is suppressed, species that need fire to regenerate will slowly die without ever releasing their seeds, and species dependent on those pines are consequently affected.

Pines do best in open areas and are not shade-tolerant. Generally, they don’t need rich soil and do best if it drains fairly quickly. Some can survive in harsh environments such as cold, exposed ridges at high elevations or latitudes, or even the wet and windy Pacific coast.

Wildlife value
Pines are one of the most valuable food plants for wildlife in the Pacific Northwest, particularly for small mammals like chipmunks and squirrels, as well as birds such as grosbeaks, jays, chickadees, and nuthatches who forage on the highly nutritious seeds and help distribute them. Larger birds, including woodpeckers, also use pine trees as food sources, particularly dead and dying pines. Pine needles may be eaten by some Lepidoptera (butterfly and moth) species (such as the larvae of western pine elfin that use lodgepole and ponderosa pine for food), as well as by pine sawfly, deer, and mountain goats; needles are also used in nest building. Large pines provide excellent roost and nest sites, while smaller pines offer crucial cover for many animals. Fallen needles may serve as bedding for larger mammals such as deer.

Native pines west of the Cascades
Below is info on the five native pine species that occur in the PNW west of the Cascades, plus one honorable mention; they are noted according to the number of needles per fascicle. If you want to identify a particular tree, count the needles per fascicle, evaluate the appearance of the cones, and check the natural range.

Fast-growing Pinus contorta evolved into four varieties, each of which adapted to its geography. Despite their large ecological and morphological variability, all varieties of P. contorta have two stiff, one to three-inch long needles per fascicle, which are often twisted and are mostly found toward the ends of twigs. The seed cones are small (typically one to three inches long), hard, prickled toward the top of the cone, and found near branch tips. The varieties are inter fertile in areas where their ranges overlap.

Pinus contorta var. contorta

Three varieties are found in the PNW. It was shore pine (a.k.a. beach pine or twisted pine), Pinus contorta var. contorta, that led David Douglas to offer the species’ epithet contorta when he first laid eyes on one in 1826: Reportedly, he found some relatively short trees growing in contorted and gnarly outlines near the mouth of the Columbia River on wind-swept, rocky sites with the added insult of oceanic salt spray. Bark is thick, deeply grooved, and a deep red-brown in color. Small brown cones are often asymmetrical and release seeds at maturity. Adapted to poor and rocky soils, shore pine’s range includes the San Juan islands, the outer coasts of British Columbia, Oregon, Washington and northern California, bogs of Alaska and Washington, and only occasionally the Puget-Willamette Trough. On more sheltered sites, this coastal species will grow taller and more erect (up to about 50 feet tall), and slightly resembles the appearance of Pinus contorta var. latifolia (lodgepole pine), which naturally occurs further inland, mainly in the Washington Cascades east of the Puget Trough and at higher elevations (up to 11,500 feet).

Lodgepole pine grows taller (up to ~100 feet) and more slender (especially when growing close together) with thin bark and a narrow crown. Adapted to stand-destroying fire, it is one of the first trees to come back after a natural periodic fire; its cones, which vary in shape and may be solitary or paired, are considered fire-dependent. However, this cone characteristic varies with tree age and local fire history, with older trees and those growing in areas with frequent fires able to produce serotinous cones. Remarkably, some lodgepole pine trees are even more variable, having both serotinous and nonserotinous cones, which may enable future trees to adapt to change.

Pinus contorta var. murrayana, Sierra-Cascade lodgepole pine, grows in the eastern Cascades of southern Washington, Oregon and the mountains of California. Its cones usually open on the tree when mature, before a fire. Both lodgepole pines will grow in situations that other conifers cannot tolerate.

Another tall, handsome pine is Pinus ponderosa, or ponderosa pine (aka western yellow pine), a fairly fast-growing tree to 100 feet by 25 feet in cultivation, larger in natural areas. With bundles of three long, pointed bright green needles that fall off after several years, ponderosa pine has a straight, robust trunk and a wide, open, cylindrical crown when mature. Bark is furrowed and dark on young trees; on older trees the thick, fire-resistant bark typically turns a golden brown or cinnamon color, flakes off into scaly plates separated by deep fissures, and has a vanilla scent in heat. Tan to reddish-brown, conical or egg-shaped female cones have stiff prickles that curve outward. The root system spreads widely and has a deep taproot. Although best grown in full sun with well drained, deep, somewhat moist soil when young, ponderosa pine is reportedly adaptable to a variety of elevations, soil and humidity, and is drought tolerant when established. Damage may occur due to late frosts.

Lustrous needles of Pinus ponderosa subsp. Benthamiana.

Ponderosa pine is subdivided into five subspecies; P. ponderosa subsp. ponderosa is most commonly found in cold, dry environments east of the Cascade summit, throughout the Rocky Mountains and southward. Pinus ponderosa subsp. Benthamiana (aka Pacific ponderosa) is endemic to the Willamette Valley (where it is sometimes called Willamette Valley pine or Pinus ponderosa var. willamettensis), as well as the mountains of southwestern Oregon, parts of California and a few sites in western Washington. Genetically different from ponderosa subspecies in other ecoregions, it usually has longer needles (up to nine inches) and is suited to higher rainfall in valley bottoms, as well as drier slopes. Prior to 1850, it thrived in oak savanna, riparian forest and upland prairie dispersed among other species (particularly Oregon white oak, Quercus garryana). Logged extensively by settlers as they cleared the land for lumber, agriculture and other development, until recently the only remaining native stock in the Willamette Valley survived in small scattered stands. Wildlife who needed the trees for food and nesting habitat suffered from the loss, including the rapidly dwindling Lewis’s woodpecker (now extirpated; there have been no breeding records in the Puget Lowlands since 1980; the last known nest in the Willamette Valley was near Scapoose in 1970; they have not been seen in the Rogue and Umpqua Valleys since the early 1990s). While this pine does best in full sun and moist but well-draining soil, it also tolerates somewhat dry conditions and lean soils. Choose associate species from Oregon white oak (Quercus garryana) ecosystems in this post.

Another three-needled pine that possesses similarities to ponderosa pine is Jeffrey pine, Pinus jeffreyi, named by Scottish botanist John Jeffrey. A major difference is its range: In the PNW it occurs only in southwestern Oregon at 4800 to 9600 feet in elevation, often in windswept outcroppings or on serpentine and other nutrient-poor soils where it grows slowly but outcompetes other trees. In addition, its needles are a duller bluish-gray and thicker than ponderosa pine’s, and they are typically held longer (five to eight years). Cones become much larger (up to 12 inches long), with prickles that curve inward. Older bark tends to be darker and more narrowly grooved than that of ponderosa’s.

Pinus attenuata (knobcone pine) also has fascicles of three yellow-green needles, which are typically three to seven inches in length and twisted. Buff colored, three to six inch, serotinous cones — that let go of seeds only after fire melts the resin — have knobby bumps on one side, and grow in bristly, dense clusters. Bark is dark with loose, scaly plates on this very long-lived, relatively small (30 to 50 foot) tree with a conical crown; it may be shrubby on poor sites. In the PNW west of the Cascades it’s found mainly in southwestern Oregon on rocky slopes at high elevations that are prone to fire (often on serpentine soils), as well as further south into parts of California and Baja.

Pinus lambertiana (sugar pine) is a very large tree (120 to 200 feet tall) that has fascicles of five pointed needles that are two to four inches in length and striped with white on all three sides. Woody cones are straight and grow very large (up to 19 inches), with straight, thick scales. Bark is reddish-brown to purplish and furrowed; on young trees it’s broken into narrow plates and on mature trees broken into long plates. It’s found at mid to high elevations in the mountains of southern Oregon (from Linn County, southward), as well as southern California, the Sierra Nevada range and northern Baja. David Douglas named the species lambertiana in honor of the English botanist Aylmer Bourke Lambert in 1826.

You may be familiar with Pinus monticola, Western white pine, since it is fairly easy to grow (despite its susceptibility to white pine blister-rust). A large, symmetrical tree (to 130 feet but smaller in cultivation), it also has fascicles of five needles, but white pine’s thin bluish-green needles have (surprise!) white lines on two sides of each 3-sided needle. Slender, curved woody cones are four to ten inches long, with scales that are thin and may be curved but without prickles. Bark is gray, thin, and broken into small rectangular or hexagonal scaly plates on mature trees. Range includes southern British Columbia, Washington, Oregon, and California’s Sierra Nevada, from sea level to about 2500 feet in elevation in moist valleys and open slopes.

The very slow-growing, often shrub-like or gnarled Pinus albicaulis (whitebark pine) also has short needles in bundles of five, thin grayish bark, and small roundish cones without prickles that remain closed on the tree at any age. Since it naturally occurs only at high elevations (near timberline) in southern B.C, the Olympics, the Cascades, east-central California and the Rocky Mountains, you won’t be tempted to grow it in your low elevation yard, but I’ll mention it as it certainly deserves our attention and concern.

Data from USFS Forest Inventory and Analysis surveys report that “as of 2016, 51% of all standing whitebark pine trees in the US were dead” and over half of that amount occurred approximately within the last two decades. Due to severe population decline, the USFWS determined that it “warrants protection under the Endangered Species Act (ESA), but … adding the species to the Federal List of Endangered and Threatened Wildlife and Plants is precluded by the need to address other listing actions of a higher priority.” The severe decline is attributed to multiple stressors, especially white pine blister rust (introduced into western North America through the horticulture trade in 1910 from Europe), but also outbreaks of mountain pine beetle (made worse by a warming climate), fire suppression and catastrophic fire, poor management, and, of course, climate chaos. UPDATE: In December 2022, this species was listed as threatened under the federal Endangered Species Act.

Whitebark pine is very long-lived, with some surviving 1,000 years. Considered a keystone species, it regulates runoff by slowing down snowmelt, controls soil erosion due to its ability to grow quickly after disturbances such as fires, and provides a rich source of food for birds like Clark’s nutcracker and mammals such as grizzly bears. It depends almost exclusively on Clark’s nutcracker for seed dispersal, but there needs to be sufficient density and seed abundance to attract the birds. More info here.

Try pines at home
If you want to add pines to your landscape, remember that it’s best to grow native trees and other plants that truly belong in your neck o’ the woods. Obtain plants propagated from source material that originated as close as possible to your site and with similar habitat features. Using such “local genotypes” helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants and animals adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.

Provide good drainage and enough sun and space (both above and below ground) for these beauties. Whenever possible, grow them with their natural associate species, which have similar needs, to recreate a native plant community that is able to impart the most benefits to the ecosystem and result in more habitat for wildlife. And if you have the space, plant a grove!

© 2022 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Western wallflower (Erysimum capitatum)


Unlike the proverbial human wallflower, the Pacific Northwest’s native wallflower plant (Erysimum capitatum) isn’t shy or modest. Instead, it is bright, showy, sweetly fragrant, and attractive to pollinators like butterflies and bees. Although it didn’t make it into my book, it is definitely worthy of praise and recommendation.

The genus Erysimum, a member of the cabbage (Brassicacaeae) family, contains about 150 species found throughout much of the northern hemisphere. Growth habits may be annual, short-lived perennial, or woody perennial. Carl Linnaeus named the genus after the Greek word eryomai, which means “to help or save” in reference to the medicinal qualities of several species. European folk medicine practitioners used poultices of wallflower for bronchial congestion, while Native Americans made tea with the dried leaves or seeds of wallflower to relieve stomach cramps.

In the U.S., western wallflower (aka prairie rocket, Douglas wallflower and sand dune wallflower) occurs in many different habitats throughout the west, including parts of Washington, Oregon, California, and southern British Columbia (usually below 4,000 feet). In Washington, Erysimum capitatum var. capitatum is found both east and west of the Cascades and in the Olympic Range; in Oregon it is found on both sides of the Cascades as well as westward through the Columbia River Gorge and into the Willamette Valley, and in the Siskiyous. See range map here. Several other varieties or subspecies are endemic to California; at least one (E. c. var. angustatum) is listed as endangered due to development, mining, agriculture, and invasive plants.

How it grows
Although western wallflower is technically a perennial plant, it’s often considered a biennial due to its short lifespan (rarely does it live past its second year). Like other short-lived perennials, it has a strong tendency to self-sow and is quite easy to grow from seed in pots or outdoor beds (but seeds reportedly have a short shelf life even when properly stored, so try to use them within a year or two).

Although wallflowers’ growth form and appearance vary (depending on location, light, soil, and moisture), here’s a general description: Deep green leaves — numerous, usually hairy, long and narrow — grow in a basal rosette, as well as along erect stems. Clusters of four-petalled, fragrant flowers are bright yellow to deep orange and appear at stem tips in a raceme. Bloom time is late April to August (depending on conditions and location—I’ve had them bloom until January during mild winters); the resulting fruit is a one to four inch, upright, slender, flat seed pod called a ‘silique‘. In bloom, plants may reach one to three feet tall, with a spread of one-half to two feet.


Wildlife value
Western wallflower plants are important food sources for wildlife, including the caterpillars of some lepidoptera (butterfly and moth) species, such as Sara’s Orangetip butterfly (Anthrocharis sara). Nocturnal moths and other butterflies, such as Painted Lady (Vanessa cardui), Anise swallowtail (Papilio zelicaon), Pale Tiger Swallowtail (Papilio eurymedon), and Persius Duskywing (Erynnis persius) are a few that may use the plant for nectar, as do some native bee and ant species. Mature seeds turn a deep orange and are eaten by — you guessed it — insects and birds who eat seeds.


Try it at home
Easy to grow and with a lengthy bloom period, western wallflower will brighten up any spot in full sun to light shade and looks particularly dazzling with a dark backdrop. Tolerant of drought since it typically occurs in dry, rocky, clay, or sandy locations, it needs well-drained soil to thrive, but will take artificial irrigation if drainage is adequate; additional moisture during dry months may even prolong its bloom time. Growing plants en masse, in clumps or drifts, will provide the most visual impact and support for wild ones, but they also look lovely interspersed with plants such as penstemon. Space plants about one to two feet apart.

As always, buy plants or seed propagated from source material that originated as close as possible to your site. Using such “local genotypes”  helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants (and animals) adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.


© 2020 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Red-flowering Currant (Ribes sanguineum)


Although red-flowering currant (Ribes sanguineum) is a deciduous shrub, it offers year round appeal and habitat, making it a favorite among Pacific Northwest gardeners and wildlife, alike. Not one December goes by that I don’t marvel at its ability to hold onto many of its seasonally colorful leaves until the solstice or beyond, and this year was no exception. Just a short while later — following barely two months of downtime in the new year — strikingly gorgeous flower clusters burst forth prolifically at the same time that fresh leaves emerge. No wonder another of its common names is “winter currant.” Fast forward a few more months, and dark dusty-blue berries, a favorite of many bird species, will adorn this multi-stemmed shrub. 

The sole genus in the Grossulariaceae family, Ribes means ‘currant’ in medieval Latin. One of about 30 currant and gooseberry species in the Northwest, sanguineum refers to the reddish color of the flowers. It’s one of those native plants that had to be chaperoned by Scottish botanist David Douglas to Britain—where it was introduced into cultivation in the 1820s—before it acquired a return transatlantic ticket to popularity with gardeners on its home turf. Not too small or huge, it can usually find a home in places that offer well-drained soil and at least a quarter day of sun.

How it grows
Red-flowering currant naturally occurs at the edge of forests as well as open, rocky slopes and disturbed sites, at low to middle elevations from southwest British Columbia into Washington and Oregon between the Pacific coast and the Cascades, and as far south as central California.

Wildlife value
Pendulous flower clusters, which consist of numerous lightly fragrant, pink to reddish tubular flowers, bloom in profusion along this shrub’s many stems. They offer nectar and pollen at a time when early-emerging pollinators—such as queen bumble bees who must secure a nest and provide for offspring all by themselves—have little else to eat. The early blossoms are also attractive to birds, especially hummingbirds, but also bushtits, making this species a hub of wildlife activity for well over a month. Later on, when berries ripen as summer wanes, birds such as American robins and cedar waxwings (pictured, below) feast; we can also eat them but they are rather tasteless. The small, lobed leaves may provide food for zephyr (Polygonia gracilis zephyrus), Ceanothus silkmoth (Hyalophora euryalus), and other butterfly and moth larvae, which in turn supply food for insectivorous birds. 


Try it at home
Red-flowering currant prefers sun to part sun, and well-drained soil. While tolerant of clay soils, it doesn’t do well on poorly drained sites. Useful for erosion control on slopes, it may eventually form a thicket, which is helpful for wildlife that needs somewhat dense cover.

Mature size varies from around six to ten feet tall; width is typically similar, so do allow it plenty of space so pruning won’t be necessary. A fast grower, it may reach four or five feet in just a few years and even produce blossoms as well. If you’re looking to use this shrub in a border, space them six to ten feet apart (on the low end if you want some density and overlap). Although this shrub is quite drought tolerant when established (after two to three years), water it deeply but infrequently in the hot summer months thereafter, especially if your site receives a lot of sun or reflected heat from buildings or fencing, or if drainage is quick. Plant in fall for best results.

The only downside to this lovely shrub is its relatively short life: typically just 20 to 30 years. But replacement is easy since it readily self-sows. Thus, propagation is best achieved simply, via self-sown seed, which are easily dispersed by birds or fall to the ground below. If you’d rather DIY, collect seeds as soon as fruit is ripe in mid to late summer, remove the pulp, and dry them in a shaded place; then sow in autumn (outdoors to allow for stratification). Seed reportedly has a long shelf life if stored in a cool/dry/dark place.


Grab a partner
Since red-flowering currant grows in a fairly wide range of habitats, there are a number of plants with which it interacts in intact ecosystems. For best ecological and gardening results, choose associated native plants that live in communities that currently grow or likely would have grown in your immediate area. In the Pacific Northwest, some of the plants that red-flowering currant closely associates with include Douglas-fir, bigleaf maple, madrone, bitter cherry, oceanspray, vine maple, elderberry, mock orange, serviceberry, manzanita, salal, sword fern, kinnikinnick, and others. 

Buy plants propagated from source material that originated as close as possible to your site. Using such “local genotypes”  helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants (and animals) adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.

Although many cultivars—with a range of flower color—have been developed, it’s best to choose true species or varieties found in nature. A related species for very moist places is wild gooseberry (Ribes divaricatum), which has edible fruit.

© 2019 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Oregon grape (Mahonia species)

Mahonia aquifolium (landscape)

Oregon grape plants are colorful western shrubs with year round appeal and chances are there’s a species that will fit into your Pacific Northwest landscape. Named after Bernard McMahon, an Irish-born American nurseryman, the genus Mahonia is a member of the barberry family (Berberidaceae). But you may also see Oregon grape classified as Berberis, indicative of the extensive debate among botanists on how to classify this species. Although included in the large genus Berberis (an alteration of the Medieval Latin barberis, or barberry, from Arabic barbārīs), Oregon grape is still known as Mahonia in most commercial horticulture, so either is correct (at least as far as I’m concerned!). 

Wildlife value
Like all native plants grown where they evolved, Oregon grape plants are extremely beneficial and attractive to wildlife. Flowers provide for pollinators like bees, moths, butterflies, and hummingbirds, while the fruits, which may remain on the plant into winter, are favorites among birds such as towhees, robins, and waxwings, as well as mammals. Some butterfly and moth species rely on Oregon grape plants to host their larvae, including the brown elfin butterfly. Year round cover may support arthropods, birds, reptiles, amphibians and small mammals.

Cedar waxwings feed on Cascade Oregon grape (M. nervosa). ©Eileen M Stark


Three species
You can’t go wrong with tall Oregon grape (Mahonia aquifolium) for an evergreen, erosion-controlling, woody-stemmed, slightly prickly screen, barrier or woodland border, as part of an unpruned hedgerow, or as an accent plant (pictured top). Aquifolium means “water leaf,” likely named after the lustrous, wet-looking surface of the plant’s leathery leaves that Lewis and Clark first noticed near the Columbia River. Introduced to Britain in the 1820s as an expensive ornamental, its holly-like, pinnately compound leaves begin a bronzy coppery color, then mature to a deep green, with orange, red, or purple highlights in very sunny or cold conditions. Dense clusters of showy golden-yellow, lightly fragrant flowers appear in early to late spring. Ripening in late summer, the dusty-blue, round to oblong berries are slightly reminiscent of grapes, hence the name. Although they are tart and have large seeds, they are suitable for jams and jellies (with beaucoup sweetener) and have traditional medicinal properties, as do the roots. 

Tall Oregon grape’s range includes most of western Washington and Oregon, parts of Idaho and much of California, as well as northeastern Washington and southern B.C. It can handle nearly full sun to shade, but being a woodland species often found growing in somewhat open forests, it prefers some shade (although very deep shade will result in fewer flowers and fruit). Though it does best in slightly moist, acidic, well-drained soil, it’s an undemanding plant that can handle many soil types and drought when established. However, it is intolerant of poorly drained soils and high water tables. Since it will gradually spread into a thicket via tough rhizomes, place it away from pathways and allow it to eventually spread into a wildlife protective clump. If you don’t plan for its growth or it somehow gets out of hand, roots may be occasionally pruned and stems may be cut (as seldom as possible) nearly to the base for renewal. Arching stems typically reach four to eight feet in height, sometimes on the lower end in garden situations.

Try growing it with trees and shrubs such as Douglas-fir, western hemlock, ponderosa pine, vine maple, Indian plum, oceanspray, serviceberry, salal, and smaller companions like sword fern, western columbine, fleabane, delphinium, and others.    

Cascade (or long leaved) Oregon grape (Mahonia nervosa) is another handsome plant, but this one grows only up to about three feet tall,Mahonia nervosa often lacks shiny leaves, and very slowly spreads into a lovely, evergreen, soil-stabilizing ground cover over many years. Nervosa means “having distinct veins or nerves” and refers to the leaf venation. Showy, fragrant, erect, pale to bright yellow flowering stalks, which put on their show in early to mid spring, are trailed by the familiar deep blue berries in late summer to fall. 

This species naturally occurs in moist to dry forests, at low to mid elevations mainly west of the Cascades including Vancouver Island, often with oceanspray, osoberry, vine maple, sword fern, salal, and oxalis, but it’s also an associate of the drier Oregon white oak and madrone habitats. It prefers shade to part shade in moist, acidic soil, but can handle drought in cool areas when established. It’s a nice substitute for invasive English ivy.

Low (or creeping) Oregon grape (Mahonia repens) is an evergreen ground cover that grows one to two feet tall and four to six feet wide. It has a large range in the west; in Washington and Oregon it is mainly found east of the Cascades growing in conifer forests, so it does well in dry, shady conditions but can take some sun. Its leaves (pictured below) may be glossy or dull, tend to be rounder and—though toothed—feel less prickly than tall Oregon grape. In nature, where its range sometimes overlaps with tall Oregon grape (and in garden situations where we often place plants that Mahonia repensdon’t belong together), it may hybridize with its cousin and produce plants that are a bit taller than the true species. 

 

 

 

 

 

 

Propagation 
All Oregon grape species are best grown from seed (without drying them), with at least three months of cold stratification outdoors (wet, pre-chilled seed may also be planted in spring). Seed germination is reportedly erratic and unpredictable. If you have established plants you may find their progeny beneath them or elsewhere, as seeds are dispersed by birds and mammals; anything but very small transplants may not survive. Cuttings may also be tried in late fall. 

As always, buy plants propagated from source material that originated as close as possible to your site. Using such “local genotypes” helps ensure that you get plants that are well adapted to your area and that genetic diversity—which helps plants (and animals) adapt to changing conditions—is preserved. Ask growers and nurseries about their sources if you’re unsure.

Do you have Oregon grape but aren’t sure which species you have? This page has a handy leaf comparison (see photo on lower right column).
 
 
© 2019 Eileen M. Stark

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Summer Berries for Pacific Northwest Birds (and You!)

Amelanchier alnifolia (fruit)

The delicious fruit of Western serviceberry (Amelanchier alnifolia).

 

If you love berries (who doesn’t?) and wildlife, you can’t go wrong with the addition of native berry-producing plants to your yard. Local native plants are crucial for native wildlife because they (unlike non-native plants) are the chief producers of insects and other arthropods that are essential to wild species’ survival, but some plants also provide highly nutritious, often tasty fruit that just happens to show up when nesting season slows down and when we develop a craving for fresh, seasonal delicacies.

When we usually think of fruit, we visualize those fleshy, sweet treats like apples and peaches. But botanically speaking, “fruit” refers to the seed-bearing structure of angiosperms, or flowering plants. Angiosperms’ fruit results from pollination of the flowers, and enables dispersal of each plant’s seeds. Their fruit may be dry, such as the seeds of grasses or milkweed, or they may be fleshy, as in the case of huckleberries, false solomon’s seal and fairy bells.

Most native fruiting plants that appeal to us don’t ripen until late in summer, but here are a few that produce mainly during the early to mid-summer months and naturally occur widely In the Pacific Northwest, west of the Cascades. (Those that produce fruit for late summer and winter will be covered in another post.) I’ve chosen the tastiest ones and you will have to beat the birds to them if you want a sample (but do try to share!). 

Western (or Pacific or Saskatoon) serviceberry (Amelanchier alnifolia) has about as many common names as it does attributes. Also called shadbush or juneberry in some parts of its large range, this attractive, deciduous large Amelanchier alnifoliashrub or multi-stemmed small tree produces fragrant, five-petaled white flowers in early to late spring that supply food for native bees, hummingbirds and butterflies. Beautiful bluish-green leaves—that provide food for many types of butterfly larvae—turn gold to reddish-brown in autumn. Delicious “berries” (botanically speaking, a pome, pictured above) attract all sorts of birds—robins, chickadees, tanagers, waxwings—as well as mammals such as raccoons, foxes, and bears. The fruit—high in vitamin C, manganese, magnesium and iron—is at its sweetest ripeness when it turns deep purple to almost black; this is usually in early summer (hence the name Juneberry), but it may occur later depending on the location. 

Typically found growing in dry woodlands or on open hillsides in well-drained soil at low to mid-elevations, serviceberry plants are quite drought tolerant once established. They do best apart from the roots of closely competing plants, and if you’re growing more than one, space them at least 6 to 8 feet apart. They’re a great addition to large unpruned hedgerows, hillsides, or anywhere you want a screen or windbreak. Offer full to mostly sun in cool areas, part shade in hotter spots, and well-drained soil. Consider growing serviceberry with associate plants like Oregon white oak, Douglas-fir, Oregon grape, white spiraea, and others. 

Several so-called brambles, members of the large Rubus family, offer tasty “berries,” which are are actually aggregate fruit, in this case made up of many individual fruits called drupelets which developed from multiple ovaries in a single flower. Besides offering fruit that appeals to two-legged creatures, these Rubus species are choice wildlife plants that provide for pollinators, fruit-eating birds and mammals, and browse species who consume twigs, stems, bark or leaves; their thickets also provide important cover for small animals.  

Blackcap raspberry (Rubus leucodermis var. leaucodermis) isn’t your typical, cultivated raspberry, but its habit is similar: Deciduous and prickly, this vine-shrub arches up to six or seven feet tall. The stems are biennial, with fruit forming their second year. Stems that have fruited may be cut out at the base (be sure to wear gloves and long sleeves when pruning or picking fruit!). 

Rubus leucodermisMid to late spring flower clusters offer nectar and pollen for native bees; the soft fruits ripen in summer when they reach a deep purple (mid-June into July in my low elevation yard). Like all wild fruits, they are very high in nutrients such as vitamin C and antioxidants (this has been confirmed by an informal survey of American robins who greatly preferred the wild to the cultivated). But not only robins: grosbeaks, jays, thrushes, sparrows, towhees and many other birds love them, as do mammals like raccoons, opossums, foxes, and squirrels. And for small animals seeking protection from predators, a thicket of prickly stems can come in very handy. 

R. leucodermis

Native bumble bee foraging at a blackcap raspberry flower.

Found naturally in open forests and moist rocky areas, it seems to thrive in both sunny and shady sites. Though not fussy about soil type, it will fruit best when kept moist. Due to its potential to travel, I have mine in a huge pot so it doesn’t take over my minuscule yard. But if you have some space and don’t mind its spread and hooked prickles, by all means find a spot. It’s an attractive plant that bears tasty fruit, but it’s best when allowed to naturalize in a wildlife garden where its function will be appreciated.  

 


Thimbleberry (Rubus parviflorus) is another easy and fast growing bramble,Thimbleberry that comes without prickles. Its large, deciduous, soft and velvety leaves may be used by leafcutter bees for nest building.

Showy, five-petaled edible white flowers appear in late spring at the tips of young stems and provide for butterflies and bees; the tasty, bright red raspberrylike fruit ripens over the summer and appeals to many bird species, as well as small and large mammals.Rubus parviflorus (fruit)

 

 

Since thimbleberry naturally occurs in riparian areas and in open, moist to dry wooded areas, it is tolerant of moist or dry soil and full sun to partial shade. It will spread, so like cousin blackcap, it’s best in wilder gardens.

 

 

 

One other summer berried Rubus shrub is salmonberry (Rubus spectabilis), that stands out in early to mid-spring with bright pink to magenta flowers that attract migratory Rufous hummingbirds on their long journey northward, as well as other pollinators. Golden to reddish-orange raspberrylike fruit ripens in early to mid-summer and attracts the usual suspects. Its arching stems (sometimes prickly) rise up to 12 feet and spread by branched rhizomes into thickets. Typically found growing in riparian areas or the dappled shade in moist woods, it does best with moist soil but may spread more slowly without it. 

Last but not least, red huckleberry (Vaccinium parvifolium) is such a beautiful plant — and with delicious berries — that it deserves a post all its own.

 

© 2019 Eileen M. Stark

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Pacific Northwest Native Plant Profile: Alumroot (Heuchera species)

Heuchera micrantha

Alumroot or Coral bells, common names for plants of the genus Heuchera, now come in a huge array of cultivars that offer a dazzling variety of flower and leaf colors, sizes, and textures. Some, like ‘Chocolate Ruffles’ and ‘Ginger Peach,’ sound almost good enough to eat. So why would anyone want to grow the plain old native ones? 

The Pacific Northwest supports many native Heuchera that are not extraordinarily flashy, artificially-bred prodigies. Instead, they are charming, understated perennials that provide for native pollinators and contribute to the food web that is the backbone of nature’s ecosystems. Breeders’ breakthroughs do nothing for your local ecosystem, so if a true native Heuchera naturally occurs in your area and you find it for sale locally, choose it over those that were created intentionally by humans strictly for looks. 

The genus Heuchera (pronounced HOO-ker-a or HUE-ker-a), with 37 North American species to its name, was named by Carl Linnaeus in honor of a friend, the 18th-century Austrian-born medical botanist and professor of medicine Johann Heinrich von Heucher. A member of the saxifrage family (Saxifragaceae), some of its native cousins include Tolmiea (piggy-back plant) and Tiarella (foamflower). Perhaps the ease of hybridization in the nursery stems from a propensity to hybridize in the (impaired) wild: Heuchera species usually stay true in the wild since they are naturally isolated from other Heuchera species, but climatic fluctuations have caused range extensions and contact among species, resulting in hybridization and persistent hybrid populations.

Heuchera species west of the Cascades

Small-flowered or crevice alumroot (Heuchera micrantha), pictured above and right, naturally occurs in coniferous or mixed forests near shaded streams and in cool, mossy rock crevices, at low to high elevations in British Columbia, Washington, Oregon and California. Its slightly wavy basal leaves — sometimes evergreen, depending on winter temperatures — grow from branched rosettes, are shallowly lobed, mature to about three inches wide, and may beH. micrantha smooth, glandular, or hairy. One to three-foot tall open panicles of tiny white flowers bloom prolifically on thin, stiff stems during late spring and early summer. Heuchera micrantha Var. micrantha has rounded leaf lobes; Var. diversifolia (syn. Var. Pacifica) has deeply lobed oval leaves and petioles with long hairs.

Grow them in humusy soil in partial to nearly full shade or in shady rock gardens or rock walls where roots can stay cool. The flowering stems may get a bit floppy, so place them away from well-used pathways where they might get trampled. I have mine growing amongst rocks on a slight slope where they get about a couple of hours of morning sun. They increase very slowly via rhizome or seed. 

Smooth alumroot (Heuchera glabra) appears somewhat similar to H. micrantha. Its range includes British Columbia, Washington and Oregon, where it grows on moist rocky cliffs, in mossy meadows, and along stream and river banks, at low to mid-elevations. Round basal leaves are hairless, with five sharp-toothed, deep lobes and long, hairless petioles. Tiny, numerous white flowers bloom in sprays atop wiry stems. Similar cultural needs as above.

Green-flowered, or meadow alumroot (Heuchera chlorantha) naturally occurs in British Columbia, Washington and Oregon, with a wider range in Oregon.Heuchera chlorantha and friend It’s found on moist prairies or meadows, grassy bluffs near the coast, forest margins, and rocky stream banks in sun to partial sun. Arising from a branched crown with short, thick
rhizomes, its basal leaves are nearly round and shallowly lobed. Tightly spaced clusters of green or white flowers top the fuzzy stem, which can grow 1 to 3 feet tall (pictured, right). It blooms from late spring into summer. Grow this gem in more sun that the previous two.


Wildlife value
The flowers of native Heuchera attract native bees and hummingbirds. The plants’ foliage feeds insects (which in turn feed other wildlife), provides cover for small creatures, and protects the soil. H. micrantha is a host plant for Greya politella moth larvae, which feed on its stems. 

Try them at home
Heuchera species like moist soil that’s rich in organic matter and drains well. As with most plants, deep and infrequent irrigation (especially the first few years) will help obtain the deepest roots possible, which help sustain them during periods of drought.

H. chlorantha leaf

H. chlorantha leaf, round and with hairy petioles.

 

© 2019  Eileen M. Stark

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Pacific Northwest Native Plant Profile: Pacific Red Elderberry (Sambucus racemosa var. racemosa)

Sambus racemosa

Respect your elders! Words of wisdom to be sure, and I can’t help but apply them to elderberry shrubs as well. Long regarded as weedy, native elderberry approval ratings are inching up due to their ecological, medicinal, and ornamental charms.

Besides having good looks and high wildlife value, the botanical name given to this deciduous shrub attests to centuries of use by humans. The genus name, Sambucus, comes from Latin (sambūcus), from Ancient Greek σαμβύκη (sambúkē, “sambuca”), and ultimately from Aramaic ܣܐܒܒܥܚܐ‎ (sabbekha). It originates from the plant’s association with an ancient musical wind instrument of Asian origin, known as the sambuca, made from the branches of a species of elderberry. According to Wiccan lore, it was used to summon spirits. The epithet of the Pacific Northwest’s red elderberry — racemosa — refers to its unbranched inflorescence (a raceme) with multiple short-stalked flowers. The common name, elder or elderberry, is thought to come from the the Anglo-saxon aeld, meaning fire, since the hollow stems were used as bellows to blow air into the center of a fire (but don’t you dare place elder wood, also called “Witch-wood,” in the fire or it will cause it to die out, according to The Wicca Garden by Gerina Dunwich).

Most elderberry species are native to the northern hemisphere, but no matter where they grow, they’ve been used in cooking, in the making of dye or ink, and as medicine. According to folklore, elder is said to ward off and cure disease and offer protection from lightening, saddle sores and all forms of evil. As far as consuming elderberries, they are reportedly highly nutritious and not toxic when fully ripe. However, I suggest erring on the side of caution and cooking them first since unripe, bitter-tasting fruit may cause stomach upset. Cooked berries (with seeds strained out) are tart but can be made into wine, jelly, preserves, syrups, or sauces. Seeds, roots, flowers, green fruit pulp, and leaves create cyanide-producing glycosides. 

Classification
There’s been quite a bit of bickering and confusion in the literature over the classification of Sambucus species. Historically, Sambucus racemosa (native to Europe and Asia) was commonly called European red elder, while the very similar North American native Sambucus pubens (syn S. racemosa var. pubens), native to eastern North America, was known colloquially as American red elder. Some authorities have now grouped both of these red elders together under the name of Sambucus racemosa, while others have included several former species, S. callicarpa and S. pubens, as part of the subspecies Sambucus racemosa var. racemosa, which is native to the Pacific coast states. The genus Sambucus was previously placed in the honeysuckle family (Caprifoliaceae) but recently was reclassified as a member of the small Adoxaceae family, which includes Viburnum.

Sambucus racemoca
How it grows
A large, handsome, deciduous, upright perennial shrub, Pacific red elderberry rises from several tightly clustered basal stems. Pinnately compound, lance-shaped leaves with downy undersides that may grow to six inches long are striking in themselves but take a back seat when lacy, conical to egg-shaped panicles of small creamy-white fragrant flowers steal the show in late spring to early summer. A few months later, the pea-sized, berrylike fruits, known as drupes, ripen to a brilliant red.

In the wild, it may grow up to 18 feet in height and about 8 to 10 feet in width, but may stay smaller in garden situations. Though it shows a preference for partial shade, it will tolerate full sun or full shade, though the latter will cause it to look straggly as its branches reach for more light. It is moderately long-lived; upright branches become more arched with age. 

In the Pacific Northwest, red elderberry naturally occurs in moist to mesic meadows, grasslands, riparian areas, forests, canyons, ditches, and disturbed places at low to middle elevations from southern Alaska into California. In Washington and Oregon it mainly occurs west of the Cascades. 

Sambucus nigra ssp. caerulea Blue elderberry Wallowas

Fruits of the blue elderberry, Sambucus nigra ssp. caerulea. “Caerulea” means blue.

Another elderberry, blue elderberry (Sambucus nigra ssp. caerulea), typically grows larger (up to 30 feet tall) and develops bluish-purple fruits, often with a whitish coating, that are immensely important for wildlife during late summer and fall. It occurs widely within most western states in open forests and riparian areas and may be found on slopes where it helps control erosion. Plants subjected to drought may develop interesting gnarly branches and stockier trunks with age. 

Wildlife value
Elderberry shrubs provide food, cover, and nesting provisions for many wildlife species. Flowers provide nectar and pollen for butterflies, bees, hummingbirds and other pollinators. Fruits (when fully ripe) are eaten by many mammals and birds; red elderberries are the main ingredient of band-tailed pigeons’ summer diet. Some native birds and bee species use the plants for nest structure and the leaves may be used for nest material. Both red and blue elderberry are hosts for the caterpillars of the echo azure butterfly (and possibly other lepidoptera). 

Try it at home
Since elderberry plants are typically fast growing, they’re perfect for young gardens, where they can provide screening and structure overnight (well, almost). Although pruning them back can usually be done without killing them, they’re best left to do what nature intended, so be sure you give them enough space! (If you find yourself with saw in hand, remember this superstition: You must apologize three times to an elder when pruning it or cutting it down; otherwise bad luck will befall you.) 

With ample space, elderberry shrubs make stunning focal points, living screens, shrub borders or wide hedges, and provide connectivity between low perennials and tall trees, as well as erosion control along the edges of streams and ponds. Plant several to encourage more flowers and fruit.

They’re easy to grow when a few guidelines are followed. Sun: Partial shade to full sun; the more sun, the greater the flower and fruit production. Soil: Though the perfect conditions would be moist (but well-drained) rich soil near a babbling brook, elderberries can handle dryer conditions and clay soil (not sandy soil). Though they thrive in regularly irrigated areas, once fully established they are drought tolerant, but appreciate an occasional deep drink prior to and during the Pacific Northwest’s dry summers.

Grab a partner
Growing native plants with the associated species they evolved with is best, so in the Pacific Northwest consider growing red elderberry with species such as Douglas-fir, vine maple, red-twig dogwood, osoberry, thimbleberry, orange honeysuckle, goat’s beard,  fairybells, and sword and deer ferns.

Finally, there are numerous elderberry cultivars that have been developed by plant breeders looking for certain characteristics that can be maintained through propagation, such as plant size or flower or leaf characteristics. Cultivars are not natural varieties found in nature, and although some do provide well for wildlife, studies show that many aren’t as attractive and useful; their pollen, nectar and/or fruits may be deficient in nutrients, which is especially problematic for migrating birds who need high quality nutrients that provide lots of energy. And some cultivars may actually lack nectar, or their flowers may be so complex that pollinators can’t even use them. A recent study on pollinators found that the more manipulated the cultivars became, the less attractive they were to pollinators. Moreover, genetic diversity is the foundation of biodiversity, which is the foundation for healthy ecosystems. True native species provide genetic diversity; native cultivars do not.


NOTE: An unknown species of elderberry borer has been found on elderberry plants in Washington State. Although it’s not clear from this article whether it could be a native species or an imported one, it offers information on how to monitor and manage if necessary. If the insect turns out to be non-native, here is yet another reason to buy native, locally grown plants, rather than purchasing natives or cultivars from who-knows-where that could bring in unwanted and problematic insects. 

© 2018 Eileen M. Stark 

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Fairy bells (Prosartes spp.)


When you notice the enchanting, pendant springtime flowers of fairy bells, you can almost imagine a tiny fairy jingling their corollas to create a magical sound that only she can hear. An excellent choice for moist woodland gardens or shaded perennial beds, fairybells’ genus is a member of the lily family. It had previously been classified within the Asian genus Disporum, but further analysis found that North American fairybells differ in several ways and in 1995 were ushered into the Prosartes genus. “Prosartes” means “fastened” in Greek, and refers to attachments of the fruit parts.

There are six species within the Prosartes genus, and we are fortunate that three grace the Pacific Northwest, west of the Cascades: Prosartes hookeri, P. smithii, and P. parvifolia. The latter is a rare species endemic to part of Oregon’s Siskiyou Mountains; it had always been considered a variant or hybrid of P. hookeri but recently came into its own. According to the California Native Plant Society, it is “threatened by trampling, logging and associated road usage, and road maintenance.”

Of the remaining two, the more common Prosartes hookeri (Hooker’s fairy bells, pictured above) is an upright deciduous perennial with lovely horizontally spreading branches, whose alternate leaves are arranged parallel to the ground for maximum light absorption. The upper stems and veins on the undersides of leaves are somewhat hairy. Spring blooming, bell-shaped flowers that often occur in pairs (or singly or in trios) at stem tips, are protected from rainwater by the pointed tips of leaves which channel tiny streamlets. Later in the year, oval berries, slightly tri-lobed, ripen to a bright red. They are edible, but rather bland and seedy; it’s best to leave them for wildlife or allow them to naturally propagate.

Prosartes smithii

 
Prosartes smithii (Smith’s fairy lantern, shown above) is similar, but its leaves are hairless, and its slightly larger and more cylindrical flowers (that only flare slightly at the tips) hang in clusters of two to five from the underside of stems. Their fruit is slightly tri-lobed and ripens to a golden-orange (pictured below).

How it grows
Fairy bell plants grow in moist, shaded forests or openings, from low elevations up to about 5,000 feet. Prosartes hookeri naturally occurs in British Columbia and throughout much of western Washington and Oregon, as well as northeastern Oregon and parts of eastern Washington, northern Idaho and northern and central California; in addition there is a disjunct population in Ontonagon county in Michigan’s Upper Peninsula, where it has been classified as endangered. Prosartes smithii has a smaller range—from southern Vancouver Island to Washington’s Olympic peninsula, in Oregon mainly west of the Cascades, and in northern California near the coast.

Prosartes hookeri fruit


Wildlife value
Flowers attract native bees and possibly other pollinators. Fruit ripens in mid to late summer or early fall and is eaten by ground-feeding birds such as robins and towhees, as well as small mammals like squirrels and chipmunks. Plants provide shelter for insects and other little ground dwelling creatures. 

Try it at home
Fairy bells are charming, easy-to-grow plants that ought to be grown more. Because their roots are rhizomatous, they will eventually create a small thicket, but they may be the shyest rhizomes I’ve ever encountered, at least in my yard (which isn’t exactly an intact forest): Velocity of spread is a reluctant crawl (so don’t worry about them “taking over”). Seeds do seem to propagate easily after a few years, but for these plants that is definitely an asset—I can’t imagine not wanting a lot of them!

Because they typically stay under 3 feet tall, they’re perfect a few feet in from pathways or in the front to middle of shaded beds, and although they benefit from a little bit of dappled sunlight, their tolerance for full shade seems to be fairly high. Place them, when possible, in the duff of mature trees. Leafy and woody debris is very important in the forest, and should be allowed to accumulate and decompose on the soil at home as well, since leaves, cones, fallen branches and twigs slow moisture loss and provide habitat as well as nutrients. If your soil is poor and lacking in organic matter, or if the top soil is shallow, add some low-nitrogen compost as mulch (leaf compost is good) after planting and allow whole leaves and such to continually accumulate on top to create more humus.

The leaves of Prosartes species are immune to the ravages of slugs and snails, which reportedly eat the fruits and dutifully disperse the seeds. They have quite deep (and delicate) roots, even when only a few leaves are present, so take care if you want to transplant seedlings. Those deep roots make me think that they may be more resilient and drought tolerant than we give them credit for. 

Grab a partner
Both Smith’s and Hooker’s fairy bells enjoy the company of others in the Western hemlock/Douglas-fir or coastal redwood plant community, including red alder, vine maple, osoberry, evergreen huckleberry, inside-out flower, oxalis, alumroot, trillium, sword fern, deer fern, salal, vanilla leaf, piggyback plant, foam flower, and many others.

Prosartes species are wonderful substitutes for non-native invasive ground covers such as Vinca and English ivy.


© 2018 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Pacific Madrone (Arbutus menziesii)

Arbutus menziesii bark

Although it looks exotic, Pacific madrone — a beautiful broadleaf evergreen tree with a captivating and distinctive presence that transforms with the seasons — is endemic to the Pacific coast. Its exquisite attributes — fragrant flower clusters, brilliant berries, glossy leaves, twisting branches, rounded crown, and rich cinnamon-red bark that peels from a satin-smooth trunk — please all of our senses. And for the wild ones attracted to this unique gem, its ecological gifts never disappoint.

Madrona (after madroño, the Spanish name for a Mediterranean “strawberry tree”) is the name admirers in Washington give this member of the Ericaceae (heath) family, while those in California and Oregon call it madrone or Pacific madrone. British Columbians simply use the Latin genus name, Arbutus. (The epitaph, menziesii, is named after the naturalist Archibald Menzies, a naturalist for the Vancouver Expedition that explored the Puget Sound region in 1792.)

How it grows
Pacific madrone is a large, long-lived tree that naturally occurs in a climate with mild, wet winters and dry summers, although rainfall varies substantially within its range, from the east coast of Vancouver Island in British Columbia, southward through Washington and Oregon (west of the Cascades) to San Diego County. It is often found on rocky soils and other coarse soils that retain little moisture, including the dry foothills, wooded slopes and canyons of parts of California (at low to mid-elevations); within coastal redwood and mixed-evergreen forests of California and Oregon; on dry ridge tops and slopes at low to mid-elevations along the east side of the Coast Ranges and in the Siskiyou Mountains; on warm, dry, lowland sites west of the Cascades (within Douglas-fir/western hemlock forests or Oregon white oak or tan oak woodlands); and — furthest north — near sea level on rocky bluffs and low elevation slopes. Within mixed hardwood forests — that may or may not have an overstory of conifers — its tolerance to shade varies with age. While madrone seedlings do best in partial shade and young trees can handle quite a bit of shade, tolerance decreases as trees age and for those at the northern end of this species’ range. Older trees need good light to survive and often can be found  growing at an angle, twistily and desperately reaching for the sunlight that helps ensure a long life.

Wildlife value
Wild ones are drawn like a magnet to madrone trees year round. In springtime, lovely creamy white, waxy, urn-shaped blossoms provide nectar for hummingbirds, native bees, and other pollinators.

Arbutus menziesii in flower

 

Clusters of bright red berries — that ripen in autumn and may persist into early winter — feed many bird and mammal species, including American robins, varied thrushes, band-tailed pigeons, cedar waxwings, northern flickers, quail, raccoons,  squirrels, mule deer, and bears.

Arbutus menziesii (fruit)
Habitat is provided for a variety of insects, including echo blue and brown elfin butterfly caterpillars who nibble on leaves and in turn provide dinner for insectivorous birds. Shiny, leathery leaves generally remain on branches for two years, after which they turn from vivid green to burnt orange and settle to the ground where they provide a natural mulch that protects soil microorganisms and little ground-dwelling creatures. Lofty roosting and nesting habitat is also supplied, and live trees with rotting wood offer cavities for insects as well as birds that nest in trees, such as woodpeckers and chickadees. Dead and dying trees provide even more dead wood for cavity nesters and the silent decomposers that function as nature’s recyclers.

Conservation
Unlike other trees, madrone’s fine roots have adapted to search deeply into rock fractures for stored water or “rock moisture,” making it an important plant for stabilizing slopes and cliffs and preventing landslides. In addition, it’s a valuable component of many vegetation types; for example, in mixed conifer forests like Washington’s Coast Range ecoregion (Douglas-fir/western hemlock/madrone), it provides a mid-canopy story, essential for the structural diversity of the forest.

It ought to be preserved for its own sake, for the wildlife that use it, for the ecosystems of which it’s an indelible part, and, needless to say, for those of us who revere its spectacular beauty.

Tragically, the species is currently in decline throughout most of its range, for several reasons. First, sprawling development in its native habitat has stolen many mature specimens. Though tough and drought tolerant (or more precisely, drought dependent), its roots are extremely sensitive to drainage changes, compaction, grade alteration, and other soil disturbance. Because madrone belongs and successfully grows in regional arid soil conditions that many trees cannot, landowners and developers ought to protect and save this tree at all costs.

Under natural conditions, madrone depends on intermittent fires that limit the conifer overstory (typically Douglas-fir trees). Older madrone trees can survive fire and will sprout quickly and profusely afterwards due to carbohydrate reserves within existing roots. In addition, their fruit produces many seeds, which sprout on exposed soil readily after fire. But when humans suppress and prevent natural fires, the prolonged absence of fire and consequential shade—especially on moister sites—may cause madrone trees to die.

Death or damage may be also caused by several pathogens, including a foliar fungus (Nattrassia mangiferae), commonly called “madrone canker,” that reproduces via spores and causes dieback, blackening of branches, and cankers that may spread to the trunk. A root rot, Heterobasidium annosum, can also cause serious damage. Unlike fire, “disease decreases starch accumulation in the root burl, so that declining trees are less able to resprout after the aboveground portion of the tree is killed by disease.” But prevention is possible: Susceptibility to disease is exacerbated by unnatural environmental stresses such as regular summer irrigation and the use of fungicides and fertilizers. Essentially, spores are carried by water, fungicides kill beneficial mycorrhizal fungi (symbiotic associations between the roots of most plants and fungi, which protect roots from pathogens), and studies suggest that increased soil nitrogen disrupts the mycorrhizal associations between beneficial fungi and tree roots, which in turn reduce the supply of micronutrients and water to trees, thereby increasing susceptibility to disease. Madrone trees host a large number of types of mycorrhizal fungi and have been called “a major hub of mycorrhizal fungal diversity and connectivity in mixed evergreen forests” that play a large role in forest regeneration by promoting resilience to disturbance below ground.

Madrone is also affected to a small extent by sudden oak death, a disease caused by a water-borne, fungus-like pathogen, Phytophthora ramorum, which arrived in the U.S. via live plant imports of exotic ornamentals to nurseries; it is increasingly spread by human actions, including climate chaos.

Try it at home
Despite all these threats, a madrone in the wild can live hundreds of years and may grow very large — over 100 feet tall — although in cultivation they rarely exceed 50 feet after many decades. Young trees often grow fast (up to several feet per year), while older trees typically grow at a much slower pace. In the southern, drier and warmer part of its range it grows more slowly and stays smaller.

Supplemental water after establishment is highly detrimental: Madrone cannot tolerate slow drainage, standing water, or regular irrigation during summer, which makes it susceptible to disease (as do fertilizer applications). While it has a bad reputation for being difficult to establish and isn’t for the fussy gardener, knowing what this tree needs and cannot tolerate will help ensure success. In my experience, there are seven essentials to successfully growing this tree:

1. Figure out if it historically occurred in your area. Though it’s not absolutely essential that this species likely grew in your immediate area 200+ years ago — especially since much change has occurred since then — because this tree can’t just be stuck in the ground anywhere, look to nearby natural areas to see if it might have naturally occurring relatives nearby in similar soil. In its northern range, it’s usually found growing on soils derived from glacial sands or till and gravels, while in the southern and middle parts it reportedly grows on soils derived from a variety of materials.

2. Be sure your site has the right conditions: Fast-draining, non-compacted, slightly acidic soil (pH a little less than 7), and a bright location with at least a half day of sun in northerly locations. However, seedlings need partial shade to establish, so if you have mostly sun, shield them from hot afternoon rays until well established. Site plants on a slope or area that’s elevated above the surrounding area to facilitate drainage. In my yard I tried twice to grow one-foot-tall saplings in the lowest part of my yard with sad results, despite digging in extra small rocks and gravel to increase drainage. My third attempt, which I grew myself from seed, I planted atop a short, south-facing slope, again with extra rocks and gravel. I believe that the increased drainage was what was needed; however, the seedling was also very small — only three inches tall! — so that also may have helped. Note: If you live in a very warm, dry area (such as parts of California) be sure to plant this tree on a north-facing slope, rather than in hot, direct sunlight.

3. Start with very small saplings, no more than a foot tall, as older trees do not transplant well. Once they “take,” however, young trees grow quite fast (in my yard, over a foot a year). 

4. Buy plants propagated from source material that originated as close as possible to your site. Using such “local genotypes”  helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants (and animals) adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.

5. Plant saplings in the fall, just as winter rains begin, since they establish best when they can establish roots first, then put on aboveground biomass. You can plant them in the spring, but you’ll end up worrying about how much or how often to water; during the moist days of autumn you can just let nature decide. Do not add large amounts of organic matter into the soil that could inhibit the moisture-seeking roots from penetrating to mineral soil, and do not add fertilizers that can disrupt the mycorrhizal associations between beneficial fungi and roots. Never apply fungicides or other pesticides. If you have them, add a shallow layer of acidic Douglas-fir needles since they naturally grow near madrones.

6. Give them space. To allow them to get to their full and most beautiful form, plant them at least 20 feet apart and at least 25 feet away from tall trees, especially conifers that produce deep shade. Also try to minimize soil compaction, which can be detrimental.

7. Irrigate sparingly, and preferably only during the first summer or two. During my little tree’s first spring and summer it was unusually warm and dry, and I noticed some wilting of leaves on especially warm days. I carefully (and nervously!) watered it with tepid tap water (or rain water I had collected) in the mornings around its base and outwards a few feet, keeping the leaves and stem completely dry. I did this only a couple of times a week when heat was predicted, and by the end of the summer it was in fine shape and had grown well over a foot in height. During the second summer I left it on its own, and when no wilting of leaves occurred it became clear that the little tree was self-sufficient. After another foot of growth was added, I was able to fully exhale. Sometimes a little wilting of leaves isn’t serious: when cooler nighttime temperatures return the tree may bounce back, but you’ll have to be the judge at your particular site.

Baby madrone

Baby Madrone, just 4 months after planting as a 3-inch-tall sapling. [Update, 2024: At around 9 years of age, Ms. Madrone is now 15 feet tall.]

 

 
Grab a partner
It’s best to match madrones with other species that are compatible below ground—those that have similar needs and mycorrhizal associations and that would naturally occur together in nature (if you already have some non-natives that you want to keep, be sure not to grow any that need summer irrigation nearby). Which native “associated species” you choose depends on what part of the region you live in.

Madrone most commonly rubs shoulders with mixed-hardwood tree species that often have some conifer overstory (without completely shading them).  A member of the Douglas-fir/tanoak forest, madrone makes up the secondary canopy, while Douglas-fir (Pseudotsuga menziesii) with tanoak (Lithocarpus densiflorus) typically create an overstory. Less commonly, madrone mingles with coast redwood (Sequoia sempervirens) along the northern California and southern Oregon coast, and with western hemlock (Tsuga heterophylla), Oregon white oak (Quercus garryana var. garryana), and Pacific ponderosa pine (Pinus ponderosa var. ponderosa) throughout much of its range. Washington’s San Juan Islands’ open woodlands support madrone with Douglas-fir and fescue (Festuca spp.), as well as other species such as lodgepole pine (Pinus contorta), Oregon white oak (Quercus garryana), and Rocky Mountain juniper (Juniperus scopulorum). In British Columbia, Pacific madrone grows alongside lodgepole pine. Other tree species associated with madrone include sugar pine, white fir, California black oak, giant chinquapin, bigleaf maple, bitter cherry and California laurel, according to the U.S. Forest Service. Small trees/large shrubs commonly associated include vine maple, black hawthorn, red-twig dogwood, willow, hazelnut, and red elderberry. Smaller shrub associates include manzanitas, Oregon grape, ceanothus, salal, oceanspray, poison-oak, gooseberry, wood rose, snowberry, huckleberry, and thimbleberry.

A. menziesii with oaks

Madrone mingles with Oregon white oak, aka Garry oak (Quercus garryana), in parts of its range.

 

Propagation
Pacific madrone are fairly easy to grow from seed. Collect fruit soon after it ripens, generally early to mid-fall. Because one berry can have up to 20 seeds, you won’t need more than one if you just want to grow a few trees.

Separate the seeds from the pulp of a ripe, red berry (if it has dried, soak it overnight to help release the seeds from the pulp). Place seeds in a small bowl of water for 15-20 minutes; discard those that float and allow those that sink to dry in a cool place out of sunlight. Dry seeds may be viable for a couple of years if stored properly in a cold, dry place. Place seeds on top of a fine seedling mix in autumn, either in a pot outdoors or in the soil where you want a tree to grow, and cover just slightly. I like to grow them in pots so I have a little more control, but I’ve had success both ways. If you choose to use pots, keep them moist but not wet, and keep them away from slugs and snails.

Madrone seeds reportedly are able to maintain dormancy for long periods (“scores of years”) in the soil, but when conditions are just right — cold but above-freezing temperatures and adequate moisture — dormancy is broken in late winter/early spring after cold stratification has weakened the seed coat. At that point pots should be moved into a somewhat warm (if possible), bright location, but with little direct sunlight—seedlings establish best in partial shade and will grow fairly slowly. Keep them moist, but not saturated. After they have developed their second or third set of true leaves they may be moved to bigger pots with fast-draining soil (I like to use a mix of sterilized potting soil and small gravel), handling them by their expendable first set of leaves, not their delicate stems. Water them when the top inch of soil is dry; I find it’s hard to overwater with fast draining soil, but do give them time to dry out slightly. Plant them out when they’re 3 to 10 inches tall, preferably in autumn, in the conditions described above. Don’t attempt to relocate them.

 

© 2017 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Cascara (Frangula purshiana)

Rhamnus purshiana drupe
Of the 35+ Frangula species worldwide, the Northwest’s representative is a lovely medium-sized tree or tall shrub. The first thing you may notice about Cascara (Frangula purshiana, syn. Rhamnus purshiana) is its texture: Thin, silvery gray bark that’s nearly smooth but with a patchy look, and oval glossy green leaves with veins so prominent that they make the surface wavy and crinkled-looking. But Cascara’s charm doesn’t stop there: Springtime brings loose clusters of small, pale greenish-yellow flowers that later become small red fruit (a drupe, each containing 2 or 3 seeds) that ripen to the deepest purplish-blue. In autumn, its leaves turn yellow to orange and may hang on in areas with mild winters.

Frangula purshiana is a member of the Rhamnaceae family; the species name relates to frangulanin, a peptide alkaloid. The epithet, purshiana, commemorates Frederick Traugott Pursh, a remarkably well-traveled (often on foot) 18th century German-American botanist who made major contributions to North American botany.
Rhamnus purshiana

How it grows
Cascara naturally occurs along the Pacific coast from British Columbia south into northern California, as well as parts of Idaho and Montana. It’s found in moist to dry shady forests and mixed woodlands, often along streams or in moist ravines at low to middle elevations, as well as floodplains. It grows up to about 30 feet tall and roughly half as wide.

Cascara and red alder look a bit alike; you can tell them apart mainly by their fruits and leaves. Cascara produces a red to deep purple drupe, while alder’s fruit is an inch-long woody fruit that resembles a cone, known as a strobile. The leaves of Cascara are shinier and smoother than those of alder, which are tightly rolled under on the edges.

Conservation
The dried bark of Cascara has been used for hundreds of years as a laxative—first by indigenous peoples and then commercially (sold as Cascara sagrada)—and the high demand for it has led to unethical harvesting from wild trees, which deprive the plants of their protective and essential bark. It is probable that this practice has heavily reduced cascara populations.

Wildlife value
Pollinators—such as hummingbirds and native bees—come to Cascara’s late spring flowers. Birds—including band-tailed pigeons, robins, tanagers and grosbeaks—as well as mammals such as raccoons and coyotes, are attracted to the pea-sized fruit. Birds like bushtits, kinglets, warblers and chickadees forage on insects found on leaves, twigs and bark. Cascara is a host plant for the caterpillars of gray hairstreak and swallowtail butterflies and more than a dozen moth species, which feed on its leaves. Mule deer and other mammals may use it as browse.

 

Try it at home
Cascara is a great choice for small yards or places where large trees wouldn’t thrive, and I don’t know why it’s not planted more often. Besides its beauty and wildlife appeal, it’s a fast grower that can take a fair amount of sun to full shade, but it does best in partial shade. Though it is drought tolerant when established (especially in shade), it will look and do its best with somewhat moist, well-drained soil that’s rich in organic matter. In general, trees planted in hot, sunny areas will need more water. Like us, Cascara shows sensitivity to toxic gases and tiny sooty particles that are belched out of fossil fuel powered vehicles, so it may be best to keep it away from busy streets and highways. It is reportedly fire resistant.

When planting multiple trees, place them about 15 feet apart (about 10 feet apart for shrubs used as a hedgerow). Cascara shrubs are a good substitute for invasive English laurel or Portugal laurel shrubs where they can be left unpruned.

Grab a partner
Cascara grows in the understory of trees such as big leaf maple, Douglas-fir, and western hemlock, where it might live alongside vine maple, red alder, willows, and red-twig dogwood.

It’s worth noting that some Rhamnus species, such as R. cathartica (“common buckthorn,” native to parts of Europe, northwestern Africa and western Asia), are invasive outside their natural range. R. cathartica was introduced as a garden plant and is now naturalized in parts of North America, probably because it leafs out earlier than native species, often contributing to their downfall.

 

© 2017 Eileen M. Stark

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Pacific Northwest Native Plant Profile: Broad-leaved penstemon (Penstemon ovatus)

Anna on Penstemon ovatus
Growing penstemons usually requires a valiant effort to mimic wild conditions by creating rock gardens complete with crevices that these beautiful plants’ roots can inch their way into. Most species will suffer without well-aerated, quick draining soil, and can’t live with frequent summer irrigation. Unless you reside where the soil is naturally rocky or gravelly, providing fast drainage in the Pacific Northwest can be a bit challenging. But wait! Penstemon ovatus likes and needs moisture and will usually let you manage with whatever soil you have, providing it drains well and contains a fair amount of organic matter.

Nicknamed ‘broad-leaved’ or ‘egg-leaf’ penstemon, it’s a great asset to a Pacific Northwest garden. Long-lived, upright, and nicely proportioned, it grows from a woody base with glossy, deep green, spade-shaped leaves. When in flower—typically May and June—the plants rise up two to three feet above ground. Speaking of flowers, they are gorgeous: Small (15 – 20 mm) but many, and arranged in whorls on fairly tall inflorescences, they are a brilliant blue that melds into violet and pink.

How it grows
Hardy to Zone 4, this perennial is native to parts  of the Northwest (west of the Cascade Mountains) at low to middle elevations, in damp, partly sunny to mostly shady places near forest edges, often in riparian areas. Its natural range is somewhat scattered and includes the western Columbia Gorge and parts of the Willamette Valley, as well as northern areas of the Olympic peninsula and southern British Columbia. 

Wildlife value
Penstemons, in general, are fantastic pollinator plants that are irresistible to hummingbirds, native bees, syrphid flies, beetles, ants, moths, and others, depending on the species. In my yard I’ve seen P. ovatus attracting syrphid flies, P. ovatus + tiny native beeants, bumble bees, and impossibly small native sweat bees (pictured, right), many of which nest in the ground (so please take care when applying mulch or digging in soil to avoid harming them!). In addition, small songbirds may eat the seeds that mature in summer, and foliage creates cover for tiny soil-dwelling creatures.

Try it at home
Broad-leaved penstemon likes rich soil, regular (but not excessive) watering, and virtually any light situation except very deep shade or full sun, although more sun tends to make the plants flower more. Since it is a fairly robust and versatile plant, placement shouldn’t be too difficult: In my Portland yard I find it does best in some morning sun, a couple of feet in from pathways due to its spread while in bloom. Placing multiple plants in groups or swaths, with each plant 12 to 24 inches apart, will make it easy for pollinators to find them and minimize the amount of bare soil that sprouts weedy plants.P.ovatus

As mentioned earlier, unless your soil is already high in organic matter and drains well, add some low-nitrogen compost before planting (well-decomposed leaf compost is good). I like to get plants in the ground in mid to late fall when forthcoming winter rains will help get their roots established before the demands of spring; if you plant in springtime be sure to keep them adequately hydrated, especially during that first summer. After plants are established (usually a couple of years), they should do fine with just occasional—but deep—watering. If you happen to plant them close to other plants that like frequent irrigation they will likely do fine, but don’t keep them consistently wet. Siting them at the edges of rain gardens should work, but not in the low, saturated parts. They will definitely self sow, but aren’t very assertive (volunteers are easy to pull, if necessary).

Another Northwest penstemon for moist conditions and sun to part shade is the beautiful Cascade penstemon (Penstemon serrulatus), which is found on both sides of the Cascades.

Grab a partner
If possible, grow broad-leaved penstemon with associated species that also naturally occurred in your area, to help provide an eco-functional space for wildlife. Since it naturally occurs within several native plants communities, shrubs and perennials in those communities are far too numerous to list here. For starters, in sunny sites consider serviceberry (Amelanchier alnifolia), red-twig dogwood (Cornus sericea), blue elderberry (Sambucus nigra ssp. caerulea), large leaf lupine (Lupinus polyphyllus), Douglas aster (Symphyotrichum subspicatum), Oregon iris (Iris tenax), camas (Camassia spp.), and blue-eyed grass (Sisyrinchium spp.). In shadier places try Cascade Oregon grape (Mahonia nervosa), western sword fern (Polystichum munitum), goatsbeard (Aruncus dioicus), fairy bells or fairy lanterns (Prosartes spp.), false solomon’s seal (Maianthemum racemosa), Oregon oxalis (Oxalis oregana), wild ginger (Asarum caudatum). As always, choose plants that are native to your area by buying plants that come from locally sourced material at reputable nurseries.

 

 


© 2017 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Western bleeding heart (Dicentra formosa)

D. formosa
We love Western bleeding heart (aka Pacific bleeding heart) because it’s so beautiful and delicate, especially in springtime when its leaves are fresh and flowers are bountiful. Whoever named it felt the same way, because botanically speaking it’s known as Dicentra formosa; the genus name Dicentra refers to the two nectar-bearing spurs characteristic of the flowers of the genus, and the epithet formosa derives from the Latin formosus, which means “beautiful”.

How it grows
With deciduous, finely divided, bluish-green leaves and enchanting, puffy pink flowers, it blooms from early spring into summer. In warm areas with no summer irrigation it tends to disappear after its leaves die back, but fleshy roots keep the plant alive until the following spring. Should moisture reach it during the summer or fall months, it could very well forget about dormancy and even produce more flowers in the fall. It prefers cool weather to hot, and can withstand cold winters.

Western bleeding heart naturally occurs from low to middle elevations in British Columbia and southward into Washington and Oregon (west of Cascades) and northern and central California. It thrives in part to full shade in damp forests and woodlands, in ravines, and near streams.

D. formosa + Bombus vosnesenkii

Western bumble bee feeding on western bleeding heart.

Yellow warbler + Dicentra formosa

Bleeding heart may provide food (aphids or nectar) for birds.

Wildlife value
Wildlife seems to adore this plant as much as we do, due to a variety of attractants. The nectar-rich flowers attract hummingbirds, bumble bees, and syrphid flies, while the foliage may be consumed by the larvae of clodius parnassian butterflies in parts of its range. Aphids like it too, but don’t worry—the birds who like to eat them should keep them in check (especially if you have other natives to attract them): In late April, a small flock of Orange-crowned warblers—fresh from their migration from southern California or Mexico—paused in my yard to feed quite voraciously on them for nearly a week (as well as the flowers, which they pierce to obtain the nectar); a couple of the warblers have stayed around and may be nesting nearby. In addition to birds, unnoticeable predators such as the developing larvae of some species of syrphid flies can eat as many as 500 aphids (each!) before they become adults. In landscapes where predators and prey are allowed to exist, a naturalistic balance soon results. 

Western bleeding heart mainly spreads by underground rhizomes, but it’s also figured out a way to get more mileage. The little black seeds of this plant evolved an oil-rich appendage (called an elaiosome) which ants may feed to their young. When the ants toss the unused part of the seed that’s still viable, they assist in dispersal.

The plant’s leafiness provides cover for small creatures like amphibians and various arthropods, and protects the soil as well. Reportedly, deer are not attracted to it, mostly likely because it contains an alkaloid — isoquinoline — which is toxic in large amounts.

Try it at home
This plant looks wonderful in woodland gardens growing beneath native conifers or other trees, in the company of ferns like deer fern (Blechnum spicant) or western sword fern (Polystichum munitum). It does best with light, moist soil that’s rich in organic matter. Adding a top layer of leaf compost or other organic matter (but not wood chips or bark mulch) and allowing fallen leaves to remain on soil will help maintain moisture around its roots, improve soil structure, and add some nutrients to the soil.

Keep in mind, though, that this is not a shy plant! It likes to prance around the yard so is not best for very small sites, especially if there are delicate perennials that awaken late and could be shaded out by the early arriving bleeding heart. That said, it’s not terribly difficult to remove should you decide you’ve lost affection for it later on (but don’t put its rhizomes in your home compost bins or it might spread everywhere).

Like red-flowering currant, western bleeding heart had to receive a transatlantic ticket to Europe before becoming popular in gardens here: Reportedly, when the Scottish naturalist and surgeon Archibald Menzies found it in Nootka Sound on the Vancouver Expedition in 1792, he gave it to the Royal Botanic Gardens at Kew a few years later. The plant’s seed was then cultivated in Europe, but was not known to be cultivated in the US until 1835.

Grab a partner
Western bleeding heart thrives with native conifers, and in the Pacific Northwest they might be western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), noble fir (Abies procera), Sitka spruce (Picea sitchensis), and coastal redwood (Sequoia sempervirens), depending on the location. Deciduous trees like red alder (Alnus rubra) and vine maple (Acer circinatum) also like its companionship. Understory species often found growing with it include red huckleberry (Vaccinum parviflorum), evergreen huckleberry (V. ovatum), red twig dogwood (Cornus sericea), salal (Gaultheria shallon), osoberry (Oemleria cerasiformis), false Solomon’s seal (Smilacina racemosa), Hooker’s fairy bells (Disporum hookeri), western meadow rue (Thalictrum occidentale), Scouler’s corydalis (Corydalis scouleri), stream violet (Viola glabella), ferns—such as western sword fern (Polystichum munitum) and lady fern (Athyrium filix-femina)—and mosses.

Other Dicentra species in the Northwest
The uncommon Dicentra cucullaria (Dutchman’s breeches) has white to pale pink flowers with yellow tips and occurs in parts of northern Oregon and southern Washington, mainly near the Columbia River. D. pauciflora, (shorthorn steer’s head or few-flowered bleeding heart), is native to Josephine County, Oregon and small parts of California, only at high elevations in gravelly soils. D. uniflora (steer’s head), is a rare relation that also grows in gravelly (sometimes serpentine) soils at low to high elevations in parts of the Northwest.

 

© 2017 Eileen M. Stark

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Pacific Northwest Native Plant Profile: Henderson’s shooting star (Dodecatheon hendersonii)

 

Dodecatheon hendersonii
Nicknamed “shooting star,” Dodecatheon species are delicate spring bloomers that could find a home in nearly every garden. If yours lacks this sweet little perennial wildflower that’s a member of the Primrose family (Primulaceae), by all means get outside now to witness its unusual springtime blossoms, because the plant goes dormant fairly quickly after flowering. And then add it to your shopping list.

How it grows
Dodecatheon hendersonii naturally occurs in much of California, in Oregon and parts of Washington west of the Cascades, and southern Vancouver Island at low to mid-elevations within open woodlands, forest edges, and grasslands, typically in partial shade. In springtime, the plant emerges from dormancy as a modest little clump of soft green, oval or spoon-shaped leaves. A few weeks later, a slim leafless flower stalk grows above the rosette of foliage and, after what seems like a blink of an eye, spectacular little downturned flowers emerge with magenta to pink to white petals swept backwards, looking almost as though they’d been caught in a terrific windstorm, their stamens, stigma, and style protruding forward, collectively, like miniature colorful darts. Following pollination, the flowers turn toward the stars. The ovary essentially becomes a capsule where the seeds develop and, as they mature, any remaining anthers, stigma and petals fall off. Seeds are dispersed by wind or creatures who bump into the dry scape.This image has an empty alt attribute; its file name is Dodecatheon-hendersonii-1-scaled.jpg

Wildlife value
Flowers, of course, aren’t just for our eyes. Dodecatheon species evolved to attract certain species of solitary bees, as well as native bumble bees who have the ability to vibrate flowers using indirect flight muscles (aka “buzz pollination”). While they’re collecting pollen for their young (Dodecatheon species offer no nectar), the bumble bees release pollen that’s securely attached to a flower’s anthers and transfer it to stamens with their legs and mandibles. They also do this for other flowers with tubular anthers (including tomato blossoms, so consider growing native pollinator plants to attract native bees to your veggie beds!).

Try it at home
While Dodecatheon hendersonii can handle the wet soils of the Pacific Northwest’s winter and spring, it needs to dry out a bit during the summer and fall, so if you grow this species, don’t irrigate often. Since it will take many years to form a colony, space plants in natural-looking drifts, about 12 inches apart and where they won’t be shaded out by any overzealous spring ephemerals you may have, such as tulips (or even native plants such as western bleeding heart, which is an avid but gorgeous traveler).

Depending on your location and your site’s conditions, you might find other Dodecatheon species to be a better fit. Of the nearly 20 species within the genus, the Pacific Northwest hosts several other species: Dodecatheon pulchellum looks similar to D. hendersonii but has longer leaves and naturally occurs in moist areas such as near streams, seeps, and in wet meadows at low to high elevations; D. dentatum subsp. dentatum (white shooting star) is also endemic to the PNW and the only species with consistently white petals; D. poeticum is found mostly in the arid Columbia Basin and eastern Columbia Gorge, where it prefers to grow in sandy soil that is rich in organic matter, as found in the Gorge; D. alpine grows only in moist meadows and near streams at high elevations. Less common is D. jeffreyi, which naturally occurs in British Columbia, Washington, Oregon, California, Idaho, and Montana; it is Critically Imperiled in Wyoming. And D. austrofrigidum can be found, tragically, only in small, scattered populations in Gray’s Harbor and Pacific counties of Washington, where it is listed as Critically Imperiled, and in Clatsop and Tillamook counties of Oregon, where it is listed as Imperiled: In lower elevation riparian sites, “threats [to populations] exist due to logging and grazing upstream, which contributes to flooding and erosion that negatively impacts populations.“

To make more of these wonders, collect seed in summer and plant in fall or early spring, or very, very carefully separate bulblets in your garden (that are attached to roots) after flowering and no later than autumn. Or you can simply just let them increase their numbers naturally. More detailed propagation info here.

Grab a partner
Friends and associates of D. hendersonii include Oregon white oak (Quercus garryana), madrone (Arbutus menziesii), California hazelnut (Corylus cornuta var. californica), oceanspray (Holodiscus discolor), snowberry (Symphoricarpos albus), camas (Camassia quamash), white fawn lily (Erythronium oregonum), and many others.

Dodecatheon hendersonii

 
 
 
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Pacific Northwest Native Plant Profile: Western trillium (Trillium ovatum)

Trillium ovatum

Although introductions are probably not necessary, this is Trillium ovatum, an unmistakable and endearing plant that softly lights up the vernal understory of moist coniferous and mixed forests from southern British Columbia, south to California, east to Idaho, Montana and small parts of Wyoming and Colorado, and north to southwestern Alberta. It’s part of a large genus, with about 50 other members that are native to temperate areas of North America and Asia.

Trillium ovatum’s common names are “western trillium” and “wake robin,” the latter due to its unofficial designation as harbinger of spring. Trillium comes from modern Latin, reportedly an alteration of the Swedish trilling, meaning “triplet,” which refers to its three leaves and three petals. Ovatum is derived from the Latin ovum meaning “egg-shaped,” which describes the leaf outline.

How it grows
A perennial that grows from rhizomes, it technically produces no true leaves or stems above ground; the stems are considered an extension of the horizontal rhizome. The part of the plant that we notice most is an upright flowering scape (stalk), and the leaf-like structures are bracts, but most people call them leaves because they photosynthesize. The smaller leaf-like structures just under the flower are sepals.Trillium ovatum

Trillium species are divided into two types: Pedicellate (those with flowers that have a short stalk called a peduncle) and sessile (those with flowers attached directly to the bracts). The flowers have six stamens and three stigmas. Trillium plants are very long lived and can take as long as 10 years to flower from seed. As the flowers age and following pollination, the white flowers change to pink or even burgundy. Trillium are known as spring ephemerals; as summer proceeds, they go into dormancy and mostly disappear from our view (although those that are well established or receive adequate summer water usually maintain their greenery above ground following the flowering period).

Wildlife value
Pollination happens thanks to native bumble bees, moths, and beetles. The resulting fruit is fleshy and berrylike; the seeds evolved to have fleshy elaiosomes whose nutritious proteins and fats attract muscular ants who carry the seeds back home to feed their young. After the food is consumed, they toss the still viable seed and, voila! Seed dispersal accomplished.

Try it at home
Although trillium plants are quintessential forest denizens, they usually do well in shaded to partly shaded, moist woodland gardens, or even just moist (but well drained) areas on the north or east side of houses, provided that the soil is rich in organic matter and slightly acidic (pH 5.0 to 6.5). Leafy and woody debris is very important in the forest, and should be allowed to accumulate and decompose on the soil at home as well, since fallen leaves, bark, twigs, cones, and branches slow moisture loss and provide habitat as well as nutrients. If your soil is poor and lacking in organic matter, or if the top soil is shallow, add some compost as mulch (leaf compost is good) right after planting and allow whole leaves to continually accumulate on top to eventually create more humus.

Trillium can withstand minor droughts, but occasional summer water will help keep them going until winter rains begin. Recent transplants should definitely be kept slightly moist during the first couple of summers. 

The plants you buy will likely be small, but in the right conditions and over many years they will slowly spread from rhizomes to a clump as wide as two feet. Grow them as nature would: In drifts with individual plants roughly several feet apart. Although I haven’t quite gotten around to growing them from seed, sources say that seed should be collected when capsules begin to open in midsummer. Sow them twice as deep as the seed’s diameter (or slightly deeper) in deep containers with coarse growing medium. Leave them outdoors in a shaded spot to mimic natural conditions. More detailed info on propagation here.

Some PNW associates to grow them with include Douglas-fir, western redcedar, western hemlock, Pacific rhododendron, vine maple, salal, sword fern, maidenhair fern, deer fern, vanilla leaf, oxalis, western wild ginger, and stream violet.

Other Pacific Northwest trillium
Trillium albidum occurs in most parts of western Oregon, as well as Thurston, Pierce and Lewis counties in Washington, and much of northern California. Trillium parviflorum grows naturally in southwestern Washington and northwestern T. kurabyashiiOregon. Trillium rivale occurs only in southwestern Oregon and the northernmost counties of California. Trillium kurabayashii (pictured, right) is naturally found only in Oregon’s Curry County, as well as Del Norte and Humboldt counties of California.

Only buy natives from reputable nurseries and never dig plants from the wild. And it’s true what they say about never picking the flowers—doing so may eliminate the only chance the leaf-like bracts have for photosynthesis, and cause the plant to weaken or possibly even die.

 

© 2017 Eileen M. Stark

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Pacific Northwest Plant Profile: California hazelnut (Corylus cornuta var. californica)

Corylus cornuta var. california catkins

Flowers in January? You bet. Although they’re not showy blossoms that attract most people desperately searching for signs of spring, the flowers of California hazelnut are a truly welcome sight in mid-winter to spring. Hazelnuts are monoecious plants, having both soft-yellow male catkins that dangle off the tips of leafless branches, and tiny feathery clusters of red stigmas—decidedly female—that are few and often difficult to see. Due to their timing and structure, they are pollinated by wind, not insects.

California hazelnut is a deciduous, multi-stemmed woodland shrub (or small tree), beautifully textured with soft-green, saw-toothed, velvety leaves that adorn arching branches. In autumn it turns a glowing yellow or gold. Corylus cornuta var. california (leaves)Besides seasonal aesthetic interest, it offers hard-shelled edible nuts, which typically mature in late summer to early fall.

A member of the birch family, California hazelnut’s botanical name originates from both Greek and Latin. The genus name, Corylus, comes from the Greek korulos, which means “helmet” and refers to the nearly impenetrable husk on the top of the nut. The epithet, cornuta, means “horned” in Latin and refers to a beaklike point formed by the bracts, or husk, that enclose the developing fruit.

Corylus cornuta var. californica

How it grows
California hazelnut typically can be found on moist, rocky slopes or riparian areas in the understory or at the edge of mixed forests at low to mid-elevations. The variety californica naturally occurs in southern B.C., within most counties of Washington and Oregon west of the Cascades (as well as Wallowa County in NE Oregon), and in northern to central California. Another variety,  Corylus cornuta var. cornuta, commonly known as beaked hazelnut, makes its home east of the Cascades and throughout a large portion of the U.S. According to the US Forest Service, although California hazelnut doesn’t naturally grow with other native hazelnut species, “hybridization is possible in the Willamette Valley of Oregon and other locations where it grows adjacent to European filbert (cultivars of C. avellana) orchards.” Corylus americana (American hazelnut) grows in the central and eastern U.S.

Wildlife value
Many wild species eat and disperse the nuts. Rabbits and deer eat leaves and sprouts. Cover is provided for many species of birds, as well as mammals.

Try it at home
California hazelnut doesCorylus cornuta var. california hazelnut well in sun to shade, and prefers moist but well-drained, somewhat acidic soil with a good amount of organic matter. While tolerant of clay soils, it doesn’t do well on poorly drained sites. Useful for erosion control on slopes, it will eventually form a thicket. Suckers may be removed in winter (during dormancy) to create more of a treelike form, but the habitat created by thickets favors many wild animals, especially birds seeking cover, so consider just leaving this shrub to its natural form.

Mature size varies from 10 feet to 20 feet tall, possibly more with advanced age. Spread is typically 10 to 20 feet, but usually on the lower end in garden situations. Since chipmunks, jays and squirrels love the nuts, I suggest you grow as many of these charming shrubs as possible (especially if you want to have the chance to taste them yourself!). Growing more than one shrub also increases pollination, which leads to more nuts per plant. Space them 10 to 20 feet apart (on the low end if you want some density). Though this shrub is quite drought tolerant when established (2 to 5 years), water it deeply but infrequently in the hot summer months thereafter, especially if your site receives a lot of sun or reflected heat.

Squirrel watchingTo grow this plant from seed, collect nuts in late summer or early fall while the husks are still a bit green. To make sure they’re viable, place them in a bowl of water for 15 minutes or so, and use only those that sink. Plant them outdoors, an inch or two deep (but make sure a little squirrel isn’t watching you do it!). Mature plants can also be ground layered or propagated by semi-hardwood cuttings in the fall, or suckers may be divided in early spring.

California hazelnut is a good substitute for European hazelnut or English hawthorn.

Grab a partner
Because California hazelnut grows in a variety of plant communities, it gets along well with many other species. Choose partners that would have likely grown in your area. In the Douglas-fir/western hemlock ecoregion, consider red alder (Alnus rubra), vine maple (Acer circinatum), salal (Gaultheria shallon), thimbleberry (Rubus parviflorus), sword fern (Polystichum munitum), deer fern (Blechnum spicant), and woodland strawberry (Frageria virginiana or F. vesca), among others. In the grassland and oak woodland areas of the Willamette Valley, Puget Trough, and Georgia Basin, grow it with Oregon white oak (Quercus garryana), Oregon ash (Fraxinus latifolia), cascara (Rhamnus purshiana), red-twig dogwood (Cornus sericea), inside-out flower (Vancounveria hexandra) and others. In the southern Coast Range and mountainous areas of southwest Oregon, include tanoak (Lithocarpus densiflorus), madrone (Arbutus menziesii), and serviceberry (Amelanchier alnifolia).

As always, buy plants propagated from source material that originated as close as possible to your site. Using such “local genotypes”  helps ensure that you get plants that are well adapted to your area and preserves the genetic diversity that helps plants (and animals) adapt to changing conditions. Ask growers and nurseries about their sources if you’re unsure.

© 2017 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Deer Fern (Blechnum spicant)

Blechnum spicant

Since winter is well on its way, this seems like a good time to give a nod to a distinctive evergreen fern that brings elegance and function to moist, west coast coniferous forests, as well as shady gardens. Deer fern, known botanically as Blechnum spicant, comes from a large, extended family known as Blechnaceae (the chain fern family). The genus Blechnum actually has fewer members north of the equator than south (most of which live in the steamy tropics), and a few of the Ecuadorian cousins have managed to graduate to tree fern status, topping out at an impressive 10 feet tall! But our sweet little deer fern pays no mind to their staid accomplishments and remains forever a trim forest gem with many friends and admirers.

The Latin Blechnum comes from the Greek Blechnon, an ancient name for ferns, while spicant means “spikelike.” Its spikes are fertile fronds (which can be seen in the top photo) that rise vertically above the more earthly sterile fronds that produce no spores. Leaves on both types of fronds have oppositely arranged, shiny leaflets; the fertile ones are much narrower and have two rows of sori on their undersides. Deer fern looks attractive year round and its leaves often develop a coppery-red color in early spring.

Blechnum spicant

How it grows
This long-lived fern naturally occurs in southern Alaska, coastal British Columbia, Washington and Oregon (west of the Cascades), northern Idaho where it is classified as imperiled, and coastal California, as far south as Santa Cruz county, as well as the Sierra Nevada. It also occurs in parts of Europe. In western Oregon and Washington it grows from sea level up to montane zones and dominates the understory of what little remains of moist, old-growth forests, as well as second-growth forests.

Wildlife value
As you might expect, deer fern satisfies the winter hunger of deer, but also elk, caribou, moose, mountain goats, and bighorn sheep, especially in winter. It also provides year-round cover for small birds and mammals, insects, and other little creatures. Some birds may use the leaves as nesting material.

Try it at home
Deer ferns spread by thick, short, creeping rhizomes, and the key word here is short—as in stubby—which means they don’t spread nearly as fast as I would like. They prefer the misty air created by mature forest giants, the soft, moist, crumbly soil that comes from centuries of fallen detritus, and the symbiotic support of a real forest, not the drastically altered state of rectangular urban patches with hard, compacted soil and blistering heat. But don’t let that discourage you if you have close to the conditions deer ferns need: Shaded, relatively moist, somewhat rich soil beneath the protective canopy of (preferably native) conifers. A little dappled sun is fine if you can provide some supplemental water (especially when they’re young), but don’t try to grow them in bright, fairly sunny places where sword ferns (Polystichum munitum) would do better. Allowing for a nice thick layer of compost or other organic matter (such as fallen leaves that break down by fungus and microscopic organisms) will help maintain moisture around their roots and add nutrients to the soil over time.

Although deer ferns are handsome close-up as focal plants, they are at their loveliest when grown en masse as a ground cover. Since they eventually grow to about two feet tall and wide, space them about two feet apart. Or, consider placing them a bit further apart and add the companionship of other native ground cover species that can nestle in between the ferns (but not crowd them out)—this looks the most natural and will help keep down weeds and protect the soil.

Deer fern is a good sub for nonnative invasive plants such as English ivy (Hedera helix) and bittersweet nightshade (Solanum dulcamara).

deer fern & friends

In my backyard, deer fern mingles with maidenhair fern, piggy-back plant, and red-twig dogwood, all under the watchful eye of a youthful western redcedar.

Grab a partner
Deer fern does best with many other species that grow together within native plant communities. It thrives with native conifers, and in the Pacific Northwest they may include western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), noble fir (Abies procera), Sitka spruce (Picea sitchensis), and coastal redwood (Sequoia sempervirens), depending on the location. Deciduous trees like red alder (Alnus rubra) and vine maple (Acer circinatum) also make the cut. Understory species often found growing with deer fern include red huckleberry (Vaccinum parviflorum), thimbleberry (Rubus parviflorus), salal (Gaultheria shallon), devil’s club (Oplopanax horridus), queen-cup (Clintonia uniflora), false Solomon’s seal (Smilacina racemosa), Hooker’s fairy bells (Disporum hookeri), foamflower (Tiarella trifoliata), stream violet (Viola glabella), wild ginger (Asarum caudatum), piggy-back plant (Tolmiea menziesii), bunchberry (Cornus unalaschkensis), various mosses, and other ferns such as western sword fern (Polystichum munitum), ladyfern (Athyrium filix-femina), and oakfern (Gymnocarpium dryopteris).

© 2016 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Red-twig Dogwood (Cornus sericea)

Cornus sericea ssp. occidentalis

Red-twig dogwood is one of those multitalented shrubs that grows in a variety of moist habitats, provides significant wildlife habitat, and keeps us enthralled year round. Also known as red osier dogwood and creek dogwood (among other common names), it is a multi-stemmed, deciduous, long-lived and fairly fast-growing shrub that develops into an open, somewhat rounded thicket. Its common name comes from signature reddish stems which become brightest in winter. Botanically speaking, it’s known as Cornus sericea (syn. Cornus stolonifera). Sericea comes from the Latin “sericatus,” which means “silky” and describes the soft texture of the leaves and young twigs. Stolonifera refers to its lower stems or branches that tend to tiptoe horizontally and grow roots when they touch the soil.

Besides its vibrant red stems, this plant has oppositely-arranged, deep green leaves that turn an array of colors as the days shorten in autumn. On this sunless late November day in my back yard, the leaves range from a soft gold and pale orange to deep red, and they’re becoming more purplish-red each day. Come spring, four-petaled creamy white flowers will appear in clusters in May to July and will be tailed several months later by soft white to pale blue fruit (shown above) that may persist into winter if the birds don’t devour them.
Cornus sericea

How it grows
Red-twig dogwood has a large range—from Alaska and northern Canada from coast to coast, and as far south as Virginia in the east and Chihuahua, Mexico in the west, at low to middle elevations. There are two subspecies: C. sericea ssp. occidentalis, which occurs in the Pacific Northwest, Alaska, California and British Columbia, and C. sericea ssp. sericea, which is found much more widely. Differences are miminal, with the latter having slightly larger flower petals and fuzzier leaves and shoots. Both typically occur in moist, open sites such as meadows, bogs, floodplains, and near shorelines, but they also can be found under forest canopy as well as within more open woodlands in or near riparian areas.

Wildlife value
Red-twig dogwood is important for providing diverse structure, cover, nesting habitat, and a variety of edibles for insects, mammals, amphibians, and a large number of bird species. Bees and other pollinators, such as butterflies, use the flowers for nectar and/or pollen. Birds (including waxwings, thrushes, band-tailed pigeons, northern flickers, and grosbeaks), small mammals, and bears dine on its fruits—one or two-seeded drupes which are reportedly very high in fat—in summer and fall. According to the US Forest Service, “moose, elk, deer, bighorn sheep, mountain goats, beavers, and rabbits” commonly browse the stems; twigs and new shoots provide especially delectable and nutritious winter browse. Last, but not least, this shrub provides cover and important nesting habitat for songbirds, small mammals and amphibians, as well as host plants for the larvae of butterflies like the echo blue butterfly.

Cornus sericeaTry it at home
Although fairly shade tolerant, plants growing in full sun typically grow much more compactly than those in shade, usually bloom more profusely, and exhibit more stem color. Depending on the amount of sun it receives, red-twig dogwood can grow from about 6 to 16 feet tall, and nearly as wide, so it may be best to leave it out of very small gardens. If you have the space, use it in any moist area where you’d like spectacular aesthetic appeal as well as valuable wildlife habitat: At the back of a border, next to a rain garden, as a somewhat open screen, as part of a large hedgerow, or to stabilize eroding soil on slopes. Plant it in the fall to give it an easy start in life, adding some leaf compost if your soil is in poor shape. Allow future leaves to stay where they fall.

Damp soil is important, and slow-draining soil is not a problem (although this plant shouldn’t have its feet immersed in water for prolonged periods). Though its tolerance for drought isn’t terribly high, with a little shade and soil that’s rich in organic matter, infrequent summer watering during excessively hot periods should be all that is needed once it’s established (typically just a couple of years). And, allowing for a dry period at the end of summer is actually a good and natural thing (as long as the plant looks healthy), since a bit of drought prepares the plant for winter. Red-twig dogwood is often planted at restoration sites, which are rarely watered afterwards, and most usually do fine.

Grab a partner
Since red-twig dogwood grows in such a wide range of habitats, there are a number of plant friends with which it would like to live. For best ecological and gardening results, choose associated native plants that live in communities that currently grow or likely would have grown in your immediate area. In the Pacific Northwest, some of the plants that closely associate with red-twig dogwood include western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii), vine maple (Acer circinatum), alder (Alnus spp.), willow (Salix spp.), aspen (Populus tremuloides), paper birch (Betula papyrifera), gooseberries (Ribes spp.), black hawthorn (Crataegus douglasii), lupine (Lupinus spp.), aster (Symphyotrichum spp.), and many others.


© 2016 Eileen M. Stark

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Pacific Northwest Native Plant Profile: Western Wild Ginger (Asarum caudatum)

Asarum caudatum

Western wild ginger (Asarum caudatum) is an understory plant that offers wonderful texture in the form of deeply veined, evergreen, aromatic leaves that carpet the soil in shady conditions, soil protection, habitat for tiny creatures, and unusual, secretive flowers. The genus Asarum has about 17 species found in North America, China, and Europe; the name is the Latin form of the Greek asaron, of obscure origin. The species epithet, caudatum, means “tailed” and refers to the wispy, almost whimsical appendages of the sepals, which protect the flower.

And what a flower! Burgundy with a brownish tinge and enchantingly mysterious in appearance, they typically bloom from April to July in Oregon. You may not even notice them unless you’re weeding on your hands and knees, or if you make a special point to seek out their intricate beauty at ground level. With charming little tails, a three-cornered shape, and a hairy cup that conceals the real flower, they are one of nature’s hidden little gems, observable only to soil dwellers or those two-legged creatures with a spirit of curiosity.

Asarum caudatum

How it grows
Western wild ginger is an often overlooked but ubiquitous member of various forest communities at low to middle elevations, from British Columbia south to California, and as far east as western Montana. With substantial tree cover and rich soils, these communities occur in areas with mild, wet winters and warm, dry summers, on fairly flat ground to moderate slopes, where they help control erosion. The available literature suggests that while wild ginger is not an early colonizer in the process of succession (a.k.a. “pioneer species”), it occurs in most successional communities, including stages that have some overstory canopy. In other words, they grow with established forest species that didn’t pop up overnight and won’t be found in recently disturbed areas, like clearcuts, burns, or landslides. They will do best with established native trees that offer protection and other rewards.

Wildlife value
Lustrous evergreen leaves provide protection for little arthropods and other tiny lives that frequent the forest floor, which may in turn supply food for some bird and herp species. The flowers attract beetles that (along with flies and gnats) pollinate them, as well as ants that are drawn to a fleshy appendage on its seeds that contain an oil. And it is thought that the plant may sustain native rodents in some parts of the region. Garden slugs may be attracted to wild ginger, but any slug poison used will also kill native slugs that do not harm the plant. 

Try it at home
Wild ginger is a ground cover that creeps slowly by shallow, fleshy rhizomes; the closer you space plants, the faster they will fill in (generally, about three to four feet apart is adequate). In addition to reproduction via rhizomes, it sometimes spreads by seed, thanks to ants: After they dutifully and mightily drag an entire seed back to their nest, the oil is removed for their young and the remainder of the seed, still viable, is discarded onto the soil.

Optimal growing conditions include shade to part shade and moist, rich soil. If you already have a woodland garden complete with mature conifers, your soil will probably be adequately acidic and fertile (unless you’ve been removing leaf litter and such that should be allowed to stay!). If your soil is lacking in organic matter, or the top soil is shallow, add some compost as mulch (leaf compost is good) and allow future leaves to stay put.

Since wild ginger prefers moist soil, keep new plants adequately hydrated for at least the first couple of summers, especially if your site lacks many trees or is subjected to sunlight or heat. Plant it in the fall for best results.

This plant is a possible substitute for the invasive Bishop’s weed (Aegopodium podagraria).

Grab a partner
Wild ginger is a choice perennial for beneath native conifers like Douglas-fir, Western hemlock, Sitka spruce, grand fir, white pine, and Western redcedar, as well as deciduous smaller trees and shrubs such as red alder, vine maple, and California hazelnut. It is exquisite growing amongst smaller associated species such as sword fern, deer fern, goatsbeard, fairybells, foamflower, trillium, and many others.


© 2016 Eileen M. Stark

Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Foamflower (Tiarella trifoliata)

           Tiarella trifoliata var. trifoliata    

Tiarella trifoliata, commonly called “foamflower,” is a lovely woodland perennial within the Western hemlock/Douglas-fir plant community of the Pacific Northwest. Besides having beautiful soft green leaves that are often divided into three leaflets, its sprays of delicate flowers — of the palest pink — bloom on leafy stems for an amazingly long time: From May to as late as early October. Really!

How it grows
This charming plant can be found in damp, shady forests, and near streams. It has rhizomes but doesn’t spread like typical ground cover plants; in fact, you’re more likely to find it self sowing than spreading speedily underground. There are three varieties: Tiarella trifoliata var. trifoliata, the one you’re most likely to find for sale, is found mainly west of the Cascades as well as in southern Alaska and British Columbia, at low to middle elevations. Tiarella trifoliata var. unifoliata occurs on both sides of the Cascades, west to Montana, and in B.C. and northern California, typically at higher elevations. It has more deeply lobed leaves and is one of the last wildflowers to bloom in the forest. Tiarella trifoliata var. laciniata, has a very small range—only a few counties in Washington and Oregon and parts of B.C.; its leaves are maplelike and shallowly lobed. The other North American foamflower is T. cordifolia, native to the eastern U.S.

Tiarella close-up

Tiarella trifoliata var. trifoliata’s dainty bell-shaped flowers, very close up.

Wildlife value
Foamflower’s clusters of tiny blossoms provide pollen and nectar for native bees and syrphid (aka hover) flies. Seeds are eaten by ground-feeding birds such as sparrows. Foliage provides cover for very small creatures and protects the soil.

Try it at home
Maturing to barely a foot tall and wide, it’s best grown en masse in the shade (or partial shade) of conifers where the soil is well-drained but naturally rich (or has been amended with organic matter, like compost), as well as along shaded pathways or near ponds and streams. Plant this gem in the fall for best results. If it’s not grown in a moist area, keep it happy with supplemental water during dry periods and it will self sow, but only in the most polite way.

Grab a partner
Grow foam flower with associated species such as Douglas-fir, western hemlock, western redcedar, vine maple, serviceberry, oceanspray, thimbleberry, sword fern, salal, Cascade Oregon grape, inside-out flower, oxalis, and many others.

 

© 2016 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Shiny-leaf spiraea (Spiraea lucida)

 

 

Even though it’s growing and thriving in my front yard, it took an October trip to northeast Oregon’s Wallowa Mountains to remind me why I love shiny-leaf spiraea, or botanically speaking, Spiraea lucida. In Latin, lucida means “bright,” or “to shine,” and shine it does.

Uncommon, small (as shrubs go, typically about 3 feet tall), erect (usually) and deciduous, it’s a very attractive native plant that spreads slowly by rhizomes. Though its seeds are also perfectly capable of repopulating and may be distributed by birds, rodents, or wind, I find it’s not a strong self-sower. The U.S. Forest Service affirms that “overall seed production and dispersal is low”.

Besides its relatively small stature that allows it to fit into fairly tight spots, it has many other attributes and I can’t imagine why it’s not planted more often in yards and gardens in the Northwest. It’s barely mentioned in my book, so here I give it its due.

In late spring to early summer, creamy white flowers — sometimes with a pale pink blush — show up in flat-topped clusters that are 2 to 5 inches wide. With occasional deep summer watering, it will sometimes bloom during late summer and even autumn as well. As the flowers mature they offer lovely, although fairly inconspicuous, golden brown seed heads that continue to delight.

Spiraea betulifolia var. lucidaBut the best is yet to come: Fall may be its prime season when oval to oblong toothed leaves turn lovely autumn shades. The entire little shrub lights up like a flame above the dark, moist soil and fallen leaves beneath it.

 

 

How it grows
Sometimes called white spiraea, it  naturally occurs in parts of western Canada, Washington and Oregon, and as far east as Montana. It grows along streams and lakes, in mountain grasslands and on the slopes of forests (especially rocky ones) both east and west of the Cascades, from sea level up to about 4,000 feet, although it can be found at higher elevations in moist forests. Since it’s best to grow native plants that are indigenous to your area, find out whether it occurs naturally in your county with this USDA map.

Last week I was pleasantly surprised to find it in the Wallowa-Whitman National Forest along the Wallowa Lake Trail and the Hurricane Creek Trail near Joseph, Oregon. Since these areas can get quite dry in summer, the plant’s drought tolerance is likely due to its rhizomatous ways. Often surviving in burned areas, fire kills the aboveground part of the plant, but it resprouts from “surviving root crowns, and from rhizomes positioned 2 to 5 inches (5-13 cm) below the soil surface,” according to the US Forest Service. Along the Hurricane Creek Trail, which meanders through a burned area, white spiraea was joined by “pioneer” species like western yarrow (Achillea millefolium var. occidentalis), and western pearly everlasting (Anaphalis margaritacea).

Wildlife value
The flowers—often with an extended bloom time—offer pollen and/or nectar for pollinators such as native bees, syrphid flies, butterflies, moths, wasps, and ants. Leaves and branches offer a bit of cover for small creatures, and fallen leaves protect the soil and overwintering invertebrates, which provide food for myriad other species. It’s reportedly rather unpalatable to mule deer and elk, for those of you wanting native plants that won’t get munched on overnight.This image has an empty alt attribute; its file name is S.-lucida-w-bumblebee-1.jpg

Try it at home
Shinyleaf spiraea is a fantastic little shrub that can be used in the places that a large shrub would outgrow in a few years. It’s also quite versatile when it comes to both light and moisture conditions. Since it’s an understory plant, it can handle quite a bit of shade to a fair amount of sun, but seems to do best in a mix of both. A restoration project in Montana found that the plants did much better on east or south-facing slopes, rather than west-facing slopes that endure scorchingly hot afternoon sun. At the Portland community garden where I rent a plot for growing veggies, white spiraea was planted (before I acquired my plot) in native beds that border the garden. The beds provide a little test because the sunlight that reaches them varies from just a few morning rays to about a half day of sun to nearly all-day sun. Echoing the Montana study, the spiraeas that do best are in a partly shaded area; many of the ones planted in a narrow sunny strip along a hot concrete walkway died, while those in full shade survive, but don’t look their best or flower much.

Spiraea betulifolia var. lucida

Place them about 3 or 4 feet apart and at least 2 feet from walkways, since they will eventually spread (slowly) and you don’t want to be constantly pruning them back. Amending soil with some organic matter (like compost) will help them get established, although they are quite tolerant of clay soil, as well as rocky soil. Mulch them with a natural mulch (like leaves) and keep them well watered the first 2 to 3 years, after which they should be quite drought tolerant (unless you plant them in all-day sun, which I don’t advise).

Grab a partner
Grow shiny-leaf spiraea with associated species that naturally occur in your area to help provide an eco-functional space for wildlife. It naturally occurs within Douglas-fir, grand fir, ponderosa pine, and lodgepole pine communities. Though shrubs and perennials in those communities are far too numerous to list here, consider serviceberry (Amelanchier alnifolia), red-twig dogwood (Cornus sericea), blue elderberry (Sambucus nigra ssp. caerulea), and Cascade Oregon grape (Mahonia nervosa). As always, buy plants that come from locally-sourced material at reputable nurseries.

 

© 2016 Eileen M. Stark

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Pacific Northwest Native Plant Profile: Graceful cinquefoil (Potentilla gracilis)

Potentilla gracilis with sweat-bees
Nicknamed slender cinquefoil or western cinquefoil, Potentilla gracilis is a perennial herbaceous plant. It naturally occurs over much of western and northern North America at low to high elevations, mostly in moist to dry prairie and savanna ecosystems, but also in open forests, on rocky slopes and subalpine meadows. Growing from a woody crown, it has sharply divided, oval, deep green leaves with hairy, silver undersides and somewhat erect inflorescences with bright to pale yellow five-petaled flowers that bloom from early to late summer. In the Pacific Northwest, it naturally occurs in nearly every county in Oregon and Washington, as well as parts of southern British Columbia.

Closely related species include Potentilla glandulosa (sticky cinquefoil), with cream to pale yellow flowers, and Potentilla pulcherrima, the latter of which grows in montane regions. P. pulcherrima (common name: beautiful cinquefoil) comes from the Latin pulcherrima, which means “very beautiful” (aren’t they all?). Both occur mainly in the western U.S. and Canada. There are many other species of Potentilla, but P. gracilis and P. glandulosa are the most common west of the Cascades and are the most likely to be found for sale at nurseries.

Wildlife value
Native bees, butterflies, syrphid flies, and other beneficial insects are attracted to the flowers. Graceful cinquefoil is also a host plant for the caterpillars of butterflies such as the two-banded checkered skipper. It is not attractive to deer.

Try it at home
Graceful cinquefoil does best in moist, well-drained soil that’s rich in organic matter, in full to part sun. Since it’s not a tall plant (usually no more than about two feet tall) and only grows to about two feet wide, site it where it won’t be heavily shaded by other plants. You can also grow native cinquefoil in a container, but be sure it gets enough moisture. Associated species include Cascara and Oregon ash trees, and perennials such as checker mallow, Oregon iris, native lupines, and other moisture loving plants. Summer water is essential until it’s established, but even afterwards it will do best with supplemental water during the hot, dry part of summer.

© 2016 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Goat’s beard (Aruncus dioicus)

Aruncus dioicus (goatsbeard)

I finally managed to take out a very large hosta plant in my front yard. I really hate to remove healthy noninvasive plants, however non-native they may be (especially when they’re pretty), but we all know that “pretty is as pretty does,” right? Originating in northeast Asia, hostas really have no function here other than looking nice with those ultra-inflated leaves. I don’t think I’d ever seen a native pollinator on its blossoms, let alone a nonnative honeybee. Plus, it was overpowering a fern that belongs in this neck of the woods.

In its place now is a goat’s beard plant (Aruncus dioicus) that had volunteered in the back yard, courtesy its frisky goat’s beard parents. Also known as “bride’s feathers,” it is not only eye-catching while in bloom, but has local ecological function that hostas can only dream about. It also fits well into the shade-loving native spread near the north side of my house, sharing space with a surprisingly robust western maidenhair fern (Adiantum aleuticum), evergreen huckleberry shrubs (Vaccinium ovatum), Cascade Oregon grape (Mahonia nervosa), sword ferns (Polystichum munitum), and native ground cover that includes wild ginger (Asarum caudatum) and inside-out flower (Vancouveria hexandra), all of which can be found growing with goat’s beard in nature.

Aruncus dioicus foliageWith compound, pointy, toothed leaves that have a lovely texture, this plant is particularly fetching in springtime when its leaves are new. The main show begins in early to mid-summer, when tall, feathery plumes composed of tiny, creamy-white flowers rise above the foliage. Male plants are more spectacular in flower than female, but regardless of gender, it offers a stunning presence in shaded to partly-shaded borders, under tall trees, or as a deciduous screen or short hedge.

Wildlife value
Goat’s beard attracts quite a few insect species, including native bees, syrphid flies, teeny tiny beetles, and — if you’re lucky — mourning cloak butterflies (your odds will increase if you already grow their host plants, which include native willow, birch, hawthorn, and wild rose). Small birds may eat the seeds, so leave the spent flowers to overwinter.

Try it at home
Found in most of western Washington, Oregon, and northern California, goat’s beard naturally occurs along streams, in wet ravines, and in moist meadows and forests, but also sometimes in disturbed areas such as roadsides. As such, it likes moist, rich soil (so add compost and allow nature’s mulch—fallen leaves—to remain on soil), but can handle some drought when fully established. Although it does best with at least a half day of shade, it can be grown in nearly full sun in cool, northerly locations. When goat’s beard is happy, it will stabilize soil and eventually form a large clump, 3 to 5 feet tall and as wide, so space plants 3 to 5 feet apart. Both male and female plants need to be planted nearby if seedlings are desired. Grow them with associates (those that naturally grow together and depend on each other), including Douglas-fir, western hemlock, western red cedar, vine maple, deer fern, maidenhair fern, western bleeding heart, inside-out flower, wild ginger, and western trillium. Enjoy!

 

© 2016 Eileen M. Stark

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Fragrance in a Northwest Garden: Western mock orange (Philadelphus lewisii)

Philadelphus lewisii

Had Carl Sandburg penned a poem about the way a captivating scent wafts through the air — prior to his famous “Fog” — he might have written that it approaches us “on little cat feet.” Like fog, scent is silent and invisible and adds a fresh, sensual dimension to a garden (or a walk in the woods for that matter). One of the most fragrant flowering shrubs is mock orange, and the Pacific Northwest’s native offering, Philadelphus lewisii (Western mock orange or Lewis’ mock orange), doesn’t disappoint. Plan ahead and place this medium-sized deciduous shrub where its fragrance can be noticed.

Philadelphus lewisii is named after scientist and explorer Meriwether Lewis, who collected it in 1806 during the Lewis and Clark expedition. Native Americans had numerous uses for it, including making tools, snowshoes, furniture, and even soap.

How it grows
Although there is quite a bit of individual variation within this species, the structure and growth pattern of this particular shrub goes something like this: Maturing at 5 to 12 feet tall and nearly as wide, this fairly fast grower may send out arching basal shoots as it ages, and eventually become a thicket. In late spring, flowering shoots appear, followed by vegetative growth. Rich green, egg-shaped leaves (roughly three inches long) grow in pairs along its stems. At the tips of branches, multiple clusters of white, four-petalled blossoms adorned with soft yellow stamens emerge in late spring or early summer and sparkle against a green, leafy backdrop. Flowers measure one to two inches in diameter, and offer a lovely, fruity fragrance.

Wildlife value
Mock orange’s fragrance doesn’t just appeal to us, though—it attracts nocturnal moths and butterflies like the western tiger swallowtail. As they feed on its nectar and incidentally brush against theSyrphid fly on Philadelphus lewisii flower’s anthers, thousands of male pollen particles are released, pollinating its flowers. Other pollinators attracted to scent include bees, but also syrphid flies (aka flower flies), which are particularly fond of white and yellow flowers. In late summer into winter, mock orange’s wildlife appeal continues as the plant’s tiny seeds are consumed by many species of birds, including goldfinches, as well as squirrels. It also provides twiggy cover year round.

Try it at home
Mock orange is easy to grow. It tolerates both drought (after it’s established, of course) and moisture, and will do well in full to part sun or in a fair amount of shade (but not deep, dark shade). It’s also a good shrub for stabilizing soil on slopes due to a fibrous root system. While it’s not fussy about soil, if your soil’s in bad shape consider incorporating and/or mulching with some decomposed organic matter (like compost) to get it off to a good start.

It’s best to let native plants attain their natural size and habit, but if yours was placed too close to a path or some such, pruning may be necessary. Mock orange should only be pruned soon after flowering since next year’s blossoms develop on the previous year’s growth.

Philadelphus lewisii

 

Grab a partner
Though not common, western mock orange is widespread. It occurs naturally from southern B.C. to northern California and the Sierras, and east to Alberta and western Montana, at low to mid-elevations. Growing along creeks and seeps and forest edges, on hillsides, and within chaparral and pine and fir communities, it associates with species such as Douglas-fir, oceanspray, ninebark, osoberry, baldhip rose, tall Oregon grape, and others. If space allows, try it as a member of a multi-species (unclipped) hedgerow (should pruning be necessary, do it soon after flowering, so that the following year’s blossoms aren’t affected). To stimulate flowering on older shrubs, cut back flowered growth to strong young shoots, cutting out up to 20 percent of aging stems near their base.

Other fragrant PNW plants include wallflower (Erysimum capitatum), Nootka rose (Rosa nutkana), clustered rose (Rosa pisocarpa), bald hip rose (Rosa gymnocarpa), Oregon grape (Mahonia spp.), fringecup (Tellima grandiflora), serviceberry (Amelanchier alnifolia), checker mallow (Sidalcea spp.), oceanspray (Holodiscus discolor), some ceanothus (Ceanothus spp.), bear grass (Xerophyllum tenax), milkweed (Asclepias spp.), madrone (Arbutus menziesii), and black hawthorn (Crataegus douglasii). Enjoy!

 

© 2016 Eileen M. Stark

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Posted on by Eileen Stark

Gifts of the Oregon White Oak (Quercus garryana) aka Garry Oak

Quercus garryana at Ridgefield NWR


Spring still seems out of reach, so while we’re awaiting balmier days, let’s take a moment to appreciate some of nature’s subtle, yet generous gifts. We owe everything to the natural world and even modest contact with it refreshes and offers solace. While contemplating the obvious things that nature provides—food, water, clean air—it’s easy to overlook the little (and not so little) things.

Plants, the primary producers on this planet, belong to irreplaceable, intricate, ancient ecosystems, within which they support and depend on other species—both flora and fauna— to survive. I like to think of it as everlasting give and take. This post honors one of my favorite Pacific Northwest natives whose gifts are mammoth. Quercus garryana, commonly called Oregon white oak (or “Garry oak” by those in British Columbia and Washington), is a slow-growing, very long-lived, majestic, deciduous tree that, with time, grows beautifully gnarly. As a keystone species, oak trees are vibrant communities in themselves, and support more life-forms than any other trees in North America.

Wildlife hotspot
Late last fall, while strolling along a trail at Jackson Bottom Wetlands Preserve (just west of Portland), I was awestruck by the amount of life attracted to the broad canopy of just a single mature Oregon white oak: Visible and audible were multiple white-breasted nuthatches, black-capped chickadees, downy woodpeckers, and red-breasted sapsuckers, all busily going about their foraging business with such enthusiasm that all I could do was look upwards, my mouth agape. The birds weren’t seeking the tree’s highly nutritious acorns, which sustain many other birds, as well as insects, mammals, and reptiles—they were consuming a tasty assortment of insect herbivores, which oak trees are particularly adept at generating. Studies show that the genus Quercus hosts more caterpillars and other insect life than any other genus in the northern hemisphere. This proficiency is especially important during breeding season, when the vast majority of landbirds consume and feed their young highly nutritious insects or their larvae, and other arthropods such as spiders—not seeds or fruit. Other studies show a higher diversity of bird species in oak forests than in nearby conifer forests (although pine forests are quite exceptional as well).

Like other native keystone tree species, Oregon white oak peacefully regulates ecosystem processes like nutrient cycling and energy flow, which provides benefits to wildlife (and the rest of us) that seem endless. Besides the obvious shade, beauty, and exchange of oxygen and carbon dioxide that these trees offer (trees really are the best carbon sink), inconspicuous flowers—which typically bloom in late spring—provide for pollinators like native bees, while the buds of forthcoming rounded, deeply lobed leaves play host to the larvae of gray hairstreak, Lorquin’s admiral, echo blue, California sister, and propertius duskywing butterflies. Speaking of leaves, it typically retains dead leaves on its branches until spring, a process known as marcescense. (It’s believed that marcescense, which is more common on young trees, may serve to protect new buds on branches by discouraging browsing animals from grazing. There’s also speculation that marcescent leaves help oaks create a nutrient-rich mulch when the trees need it most —in springtime. But no one knows for sure.)

In addition, cover, perches, and nesting habitat go to birds such as woodpeckers and vireos, as well as native squirrels. Oaks’ acorns sustain squirrels and other mammals, as well as many bird species. Fallen leaves, which might provide habitat for arthropods, amphibians and reptiles, slowly break down into a rich leaf mold that supports soil-dwelling invertebrates and numerous fungi that allow neighboring plants to thrive. Sugars and carbon are provided for mycorrhizal fungi, which reciprocate with nutrients for growing plants and contribute to the soil carbon pool. Intact bark creates microhabitat for mosses, as well as lichens that supply food, shelter, and nesting material, while loose bark and twigs contribute to nest building as well as browse for deer, which in turn feed carnivores like cougars.

And as oaks deteriorate with advanced age (which can be 500 years), they continue to deliver. Dead trees can last many years as snags, which provide food, nesting material, and housing to cavity nesters like owls, kestrels, woodpeckers and chickadees, as well as bats who may roost in old holes or under loose bark.

How it grows
Elevation, climate, soil, and water persuade Oregon white oak to vary immensely in habit and size. While it thrives in cool, coastal areas and near the edges of streams and wetlands where it tolerates seasonal flooding, it also flourishes in droughty inland sites where it may grow both individually and in groves on low hills surrounded by grasslands. When it occurs on gravelly sites or rocky slopes with thin soils, it often has a shrub-like or scrubby habit. Along the blustery Columbia River Gorge, where it grows with little rainfall and atop hundreds of feet of layered basalt, harshly battered trees grow gnarled but hang on thanks to a very extensive and strong root system. As seedlings, this oak’s root mass may be ten times as large as the aboveground growth.

Within the richer, deeper, riparian soils amongst tapestries of dazzling wildflowers and grasses in the Georgia Basin-Puget Trough-Willamette Valley ecoregion of British Columbia, Washington and Oregon, it acts as a keystone structure, typically growing a very broad canopy, and reaching heights 100+ feet over hundreds of years. Gigantic root systems may grow two or three times wider than the canopy. The ecoregion includes savannas (grassland with trees scattered at least 100 feet apart), upland prairies (another type of grassland), wet prairies, and shady oak woodlands with a continuous or semi-open canopy. I’ll call them, collectively, prairie-oak ecosystems.

Endangered ecosystems
To really appreciate an oak, it’s helpful to know something about its unique ecosystems that once provided some of the richest habitat in the world. The historic range of Q. garryana stretches from low elevations of southwestern British Columbia (including Vancouver Island and nearby smaller islands) to California. In Washington, it occurs mainly west of the Cascades on Puget Sound islands and in the Puget Trough, and east along the Columbia River. In Oregon, it is indigenous to the Willamette, Rogue River and Umpqua Valleys, and within the Klamath Mountains.  

When pioneers and naturalists encountered prairie-oak ecosystems, they found a breathtakingly beautiful and rich mosaic of plant and animal life. Journals of early Oregonians described massive prairies with five-mile-wide dense forests of ash, alder, willow, and cottonwood that skirted meandering rivers within floodplains. Marshes and sloughs developed during high water periods but often dried out by late summer. At higher elevations within these forest corridors were oak and associated trees. Above the floodplains were upland prairies, filled with herbaceous plants and grasses that could tolerate the parched soil of summer, as well as winter wet. Oak woodlands stood on low hills above the valley floors, surrounded by grasslands, also known as savanna.

But the landscape was not untouched or pristine. Aboriginal peoples managed parts of the ecosystems following the last glacial period, frequently using prescribed burning to boost edible plant productivity, aid the hunting of wildlife, limit the growth of conifers, and facilitate travel, particularly in the northern parts of the oak’s range. Harvesting of plants such as camas (Camassia spp.) and chocolate lily (Fritillaria affinis) also caused soil disturbance, but their eco-cultural manipulations pale greatly compared to what came later.

Since Euro-American settlement, as much as 99 percent of the original prairie-oak communities that were present in parts of the Pacific Northwest have been lost and many rare species dependent on them are at risk of extinction. Extensive destruction and fragmentation began with settlement in the 1850s, with clearing, plowing, livestock grazing, wildfire suppression, and cutting of trees for firewood and manufacturing. Prairie wetlands bejeweled with wildflowers were drained and ditched. Later, subsidies to ranchers encouraged more destructive grazing, while urban sprawl and agricultural use—fueled by human population increase—intensified. Invasion of nonnative species, and the encroachment of shade tolerant and faster growing species—that proliferate with fire suppression—outcompeted oaks and decimated additional native flora and fauna. Prairie-oak ecosystems and associated systems still continue to disappear at human hands, and isolation of the tiny remaining fragments prevents the migration of wildlife and healthy genetic material from one area to another. Other detrimental factors include diseases and parasites, climate change, and the loss of wildlife that cache acorns and perform other essential functions.  

Conservation
Despite continual destruction, there is a renewed and growing appreciation for the diversity and beauty of these habitats, motivated by recognition that we are responsible for what’s been destroyed, an admiration for the interconnected wild species the habitat supports, and a reverence for an iconic, magnificent tree. Intervention has become intensive, and collaborations and partnerships—along with private landowners, who are key partners—are working to reverse the downward trend with preservation, restoration, and management tools, although “a major restoration challenge is restoring wet prairie habitat to a level at which it can maintain resistance to invasive species,” according to the Institute for Applied Ecology.

Regeneration of oak seedlings is essential, but is often difficult. Acorns look tough, but they are viable for only about a year and may be subject to parasitism, weather extremes, and genetic isolation. Consequently, just a small percentage become trees. Two independent studies determined that oak seedlings do best when caged, but protection from other deterrents—drought, competing plants, and rodents—is important, depending on location.

Regional conservation groups include the Garry Oak Ecosystems Recovery Team and the Cascadia Prairie-Oak Partnership.

Try it at home
While the maintenance of only fragments of a past ecosystem is a poor alternative to former richness, if you live in the ecoregion (or other impoverished oak-dominated ecosystem) and want to help, choose this native tree. Even a single isolated tree can be a critical habitat structure on the landscape. It’s the only oak native to Washington and western Canada, and the dominant one in Oregon (black oak—Quercus kelloggii—is another beautiful and valuable large tree that occurs from Lane County, Oregon, south to Baja, at low to high elevations).

An Oregon white oak tree needs a mostly sunny, well-drained site that can accommodate its eventual size aboveground (25 to 100+ feet wide, depending on spacing) and enormous root systems described above. Those grown on poor, dry, rocky sites will grow quite a bit smaller and have a shrubby habit. When planting more than one, space trees 20 to 70 feet apart, using the closest spacing only in dry, rocky terrain. It may be most helpful to visit a nearby natural area and then try to mimic nature’s arrangement.

To maintain genetic integrity, always choose trees or seeds that originated from trees close to your location and from similar terrain. For best results, plant dormant saplings in late fall after rains begin. After watering, apply about three inches of an organic mulch to reduce evaporation and keep weeds (that can steal water and nutrients) down. I prefer low-nitrogen leaf compost, spread out to the tree’s drip line and kept at least a foot from the trunk to prevent rot. Oaks do not need rich soil, so don’t apply synthetic or organic fertilizer because most North American trees don’t need fertilizer and may even respond adversely to it. And please don’t use those watering (“gator”) bags that only water at the base of the trunk and may promote rot. 

Though this species is drought tolerant, provide ample summer water, deeply and infrequently until established. During the first summer I like to water roughly every five days with about 10 gallons of water that’s applied so that it sinks in slowly. During the second and third summers, water once a week, 10-15 gallons, being sure to water out to the root zone (drip line) and beyond—root spread can be more than twice that of the crown. If severe heat and prolonged droughts appear to be stressing a young tree, provide more water. After the first few years it may do fine on its own, but do water it (deeply) if it appears to be drought stressed. Keep the area well weeded and don’t stake trees unless they are in very windy areas—they’ll grow much stronger if left unsupported. Keep in mind that soil compaction, hardscape, lawns and irrigation systems around water-sensitive oaks are a major cause of their decline in residential areas. Here is more info on how to plant Oregon white oak.

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Grab a partner
As with other native species, oaks will function best when grown within a habitat and community type that consists of plants that evolved together and need the same conditions. Figuring out which community occurs in your area requires a walk in a nearby natural area where species, as well as nature’s organization, can be learned. Some associate trees that might thrive with your oak include Oregon ash (Fraxinus latifolia) on moist sites, and madrone (Arbutus menziesii) on drier sites, and Pacific ponderosa pine (Pinus ponderosa subsp. Benthamiana). For shrubs, consider california hazelnut (Corylus cornuta var. californica), osoberry (Oemleria Aquilegia formosacerasiformis), serviceberry (Amelanchier alnifolia), snowberry (Symphoricarpos albus), oceanspray (Holodiscus discolor), red-twig dogwood (Cornus sericea), and tall Oregon grape (Mahonia aquifolium), depending on your location. Sword ferns (Polystichum munitum), orange or pink honeysuckle (Lonicera ciliosa or L. hispidula), fescues (Festuca spp.), and many wildflowers, including allium (Allium cernuum), camas (Camassia spp.), meadow checker mallow (Sidalcea campestris), western columbine (Aquilegia formosa, pictured right), and shooting star (Dodecathon spp.) associate in different parts of its range.To find out which habitat type and plant communities would likely have grown in your area, check out this Ecoregional Assessment, or query your county’s soil and water conservation district or native plant society chapter. The following publications may also be helpful:
~ Georgia Basin: Garry Oak Ecosystems Recovery Team
~ Puget Trough: Prairie Landowner Guide for Western Washington 
~ Willamette Valley: A Landowner’s Guide for Restoring and Managing Oregon White Oak Habitats
~ East Cascades: https://eastcascadesoakpartnership.org

 

© 2017 Eileen M. Stark

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A Winter Delight: Licorice Fern (Polypodium glycyrrhiza)

Licorice fern (Polypodium glycyrrhiza)

When many Northwest ferns have said adiós to most of their aboveground growth and have nearly left the stage, enter licorice fern. If you have it in your yard you might forget it’s there until the soft rains of autumn release it from its dormancy. Then — when you least expect it — bright green, featherlike fronds (to about 12 inches) gradually appear to help brighten the landscape all winter long. Although licorice fern may stay evergreen where it is well established, out of harsh sunlight, and receives some moisture in the form of mist or from a watering can, it is typically a summer deciduous plant. It is a primary producer for other inhabitants within the ecosystem, including insects, birds, and other animals.

Its botanical name, Polypodium glycyrrhiza, means “many footed” and “sweet root,” and refers to creeping rhizomes that taste like licorice (which I’ve yet to try). Native Americans used the rhizome to sweeten foods and unpalatable medicines, but they also used it as medicine itself, to treat sore throats and upper respiratory infections. Modern herbalists use it for similar purposes.

How it grows Licorice fern on American elm
Licorice fern is one of those multitalented plants that occurs naturally in several habitats. The next time you walk under a massive, mature deciduous native tree like big-leaf maple or even a nonnative giant, such as American elm (native to the eastern U.S.), look upwards and there’s a good chance you’ll find it growing as an epiphyte on trunk and branch bark, particularly in crotches or on horizontal limbs that usually stay wetter than vertical ones. But it’s also found hugging dead or dying wood like logs and stumps, and as a lithophyte in rocky outcrops and mossy ledges (pictured, below).

Licorice fern (Polypodium glycyrrhiza)

 

 

 

Licorice fern naturally occurs in cooler parts of the Pacific Northwest (west of the Cascades) and near the California coast (as well as small sections of the Sierra Nevada), at low elevations. Disjunct populations in Idaho and Arizona are listed as imperiled.

 

 

Rescue mission
The ferns that now grace my yard were rescued from mature street trees that had the misfortune of being cut down or blown down in my neighborhood. The trees’ upper branches were nearly covered with the ferns, so when the fallen limbs were in the street awaiting transport, I peeled off bark adorned with the featherlike fronds, their roots firmly and securely attached to the bark. Sections of the leafy mats were placed under native shrubs and in shaded rocky areas in my yard, where the soil is fairly rich and slightly acidic, and where moss grows readily (and not too far from the hose, since I figured they would need to be kept moist for a couple of summers). I also placed some logs (leftover from fruit tree prunings) under or immediately next to those without the company of rocks. Now the mats have come to life again, and I think they are quite settled in, judging by a new little plant that’s appeared about 10 feet from its parents—spores are in the air!

Licorice fern (Polypodium glycyrrhiza)Try it at home
If you’d like to try growing licorice fern in your yard, pick a spot that’s naturally mossy, since most areas that support moss ought to be able to support this fern. And be sure that you can get to it easily with a watering can while the plants are young; they will need to be kept moist—but not saturated—until they’re established, at which time they will become self-sufficient (except during exceptionally hot periods when dormant plants will appreciate an occasional splash of water).

If moss isn’t growing in your garden, try to nestle a plant between shaded, half-buried rocks that have been enhanced with a slightly acidic, humusy and well-draining soil amendment like leaf mold. Or, try licorice fern’s close relation, Polypodium hesperium—it can take drier conditions and grows naturally in rocky places on both sides of the Cascades. Its short stature makes it a lovely addition to nooks and crannies of stone walls, as well as a candidate for creeping through a mostly shaded rock garden. Licorice fern’s other Northwest relative, P. scouleri, is a leathery-leaved gem that grows along the foggy coastline from British Columbia, south into California. But it is reportedly difficult to cultivate so should just be left alone to bask in the ocean’s salty mist.

As always, buy all native plants from reputable nurseries and never harvest from the wild. Or, rescue them from doomed situations, preferably at a time that will benefit the transition.

© 2015 Eileen M. Stark

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Best Early Spring-Flowering Shrubs for Pacific Northwest Pollinators

Ribes sanguineum

Plan ahead for hungry native pollinators who need early-flowering plants like red-flowering currant to survive.

 

April showers may bring May flowers, but what about providing forage for hungry pollinators that need food earlier in the year? To provide large amounts of nectar and pollen in late winter and early spring for emerging bees as well as hummingbirds and other pollinators, to help you endure the gray winter skies and store carbon, and to get the most bang from your buck, add early-flowering native shrubs to your garden. Get new shrubs in the ground preferably in autumn—so the plants benefit from winter rains, and to ensure that you have the early part of a continuous succession of flowers covered.

Here are five early-flowering shrubs (plus one shrubby tree that’s pollinated by wind), listed in order of size from largest to smallest, that naturally occur in large areas of the Pacific Northwest region west of the Cascades. They grow in sun to partial shade, are fairly easy to find at native plant nurseries (as well as nurseries that don’t focus on natives), and are quite easy to grow, provided they are kept adequately moist until they are established (2 to 5 years). All would do well planted in wide, unpruned hedgerows. When choosing any shrub, note its eventual width to be sure you have enough space for it to stretch its limbs and attain its natural form at maturity—and to eliminate future hack jobs by a pruner. 

Buy plants that are responsibly propagated from source material that originated as close as possible to your site. Using such “local genotypes” helps ensure that you get plants that are well adapted to your area and that genetic diversity—which helps plants (and animals) adapt to changing conditions—is preserved. Ask growers and nurseries about their sources.

Salix scoulerianaScouler’s willow (Salix scouleriana): A fast-growing deciduous shrub or small tree. Flowers are soft catkins, larger than horticultural “pussy willows,” and appear in early to mid-spring. Male and female flowers are on different plants, so grow both for seeds. Scouler willow is a larval host plant for several butterfly species. Does not tolerate full shade. Prefers moist soil. 20-30 feet tall by 10-15 feet wide at maturity. 

 

Oemleria cerasiformis

 

Osoberry (Oemleria cerasiformis): A large, arching deciduous shrub or small tree that blooms prolifically in late winter as leaves emerge. Tolerates clay soil well, but does best with some shade (nature places it in the dappled shade of tall trees). Plants are either male or female, so plant several to produce the fruit that birds need. 12-18 feet by 10-14 feet at maturity.

Amelanchier alnifolia

 

 

Serviceberry (Amelanchier alnifolia): A versatile, multibranched shrub with lovely white, fragrant flowers in mid to late spring. Bluish-green leaves turn gold to reddish in autumn. Larval host plant for several butterfly species. Needs well-drained soil with adequate organic matter. Tolerates full sun in cool areas. Doesn’t like competition, so plant other shrubs and perennials at least several feet away. 8-18 feet tall by 6-10 feet wide at maturity.


Red-flowering currant (Ribes sanguineum): An upright, deciduous shrub with nearly year-round appeal. Gorgeous, pendulous, lightly fragrant flower clusters (pictured, top) that bloom in early spring are followed by powder-blue berries. Leaves turn golden in late autumn. Larval host plant for butterfly larvae. Controls erosion. Can’t handle excessively wet soils, so be sure soil drains well and plant it away from rain gardens and other drainage areas.  7-10 feet tall by 6-9 feet wide at maturity. More info in this post. 


Mahonia aquifoliumTall Oregon grape (Mahonia aquifolium): A handsome, multitalented evergreen shrub with an upright growth habit. Bursts into flower brilliantly in early to mid-spring, for a long period. Tolerates acidic soils. Has somewhat prickly evergreen leaves, so site it where it won’t be brushed against frequently. 5-9 feet tall by 3-6 feet wide. Will spread slowly. More info in this post.

 

The earliest winter bloomer is the handsome beaked hazelnut (Corylus cornuta var. californica), a beautifully textured, large multistemmed woodland shrub or small tree that grows to 10-20 feet tall by 10-20 feet wide. It is pollinated by wind, not animals. More info here.

After planting
Add a few inches of organic matter as mulch around the shrub (but keep away from trunk) to insulate, keep weeds down, and add nutrients. Fallen leaves work well, as does weed-free compost. If you use wood chips, make sure they aren’t finely ground and/or fresh, and don’t dig them into soil—under-composted chips and bark can deplete soil of nitrogen during breakdown. Later on, simply allow fallen leaves to remain on soil to provide habitat and nutrients.

All of these shrubs are drought tolerant when established (although Scouler willow does best with supplemental summer water), but they will appreciate some irrigation in very hot situations. They should need little to no pruning if they’ve been sited to allow room for their growth.

If you already grow any of these shrubs, I’d love to hear what wild species you’ve seen attracted to them. Or how much they brighten your garden on drab winter days?


© 2015 Eileen M. Stark

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Northwest Native Pollinator Plants for Late Summer to Fall

Late season pollinator plants

Scientists know that bees are dying for a variety of reasons—pesticides, habitat destruction, drought, climate change, nutrition deficit, air pollution, and so on, which makes us the obvious perpetrator. We can help give back to them (and other pollinators) by growing flowering native plants in our gardens (as well as noninvasive exotics that step in when a native plant isn’t available or feasible), with consecutive blooms from early spring till fall. To provide for many different types of pollinators—from long and short-tongued bumblebees to syrphid flies, hummingbirds, and beetles—offer a variety of flower shapes, colors, and sizes, with smaller plants in groups of at least three of the same species (like a big, obvious “Eat Here” sign). Fragrance is also important for attracting insects to flowers and guiding them to food within the flower, and aiding an insect’s ability to efficiently learn particular food sources.

Below are some native perennials and one shrub that offer food for pollinators from mid or late summer to fall in the Pacific Northwest, west of the Cascades. There are more candidates, but I chose these species because they naturally occur in fairly large parts of the region, are generally easy to grow, and are not too hard to find at nurseries (although you will likely have to call around for availability). I’ve listed them alphabetically with some very basic care guidelines. It’s best to plant them in the fall, just before or as the rain returns.

As always, plan ahead and choose species that fit your light, moisture, and soil conditions, but also choose those that are appropriate to the natural landscape—that is, look to nearby natural areas, and add flora that would likely have grown in your area historically, if possible. You can also check a species’ natural range (to county level) here, or check with your local native plant society chapter or county soil and water conservation district. No fertilizer is necessary and please don’t use any pesticides. Keep them adequately hydrated—by watering deeply and infrequently to promote deep roots—until they’re established (2 to 5 years). Enjoy!

◊ Achillea millefolium var. occidentalis (Yarrow): Perennial. 1-3 feet tall x 1-3 feet wide. Sun to part sun. Not fussy about soil; moist or dry. Spreads by rhizomes or seed. Flat-topped clusters of white, fragrant flowers (pictured below) bloom through late summer. (Not to be confused with the Eurasian Achillea millefolium var. millefolium). Achillea millefolium var. occidentalis

◊ Anaphalis margaritacea (Pearly everlasting): Perennial. 1-3 feet tall x 1-2 feet wide. Sun to part shade. Likes moist soil with good drainage, but can tolerate drought once established. Pure white flowers are often used in dried flower arrangements. Besides providing nectar, it is a host plant for painted lady and skipper butterflies.

◊ Baccharis pilularis (Coyotebush): Evergreen or semi-evergreen shrub. 5-8 feet tall x 6-8 feet wide. Sun to part shade. Tolerates poor soils (but needs good drainage) and is drought tolerant. Flowers aren’t showy and are borne on separate male and female plants (male flowers creamy white; female pale green). Excellent wildlife habitat plant but is deer resistant.

048_Campanula rotundiflora sRGB◊ Campanula rotundifolia (common harebell): Perennial. 1-2 feet tall x 1-2 feet wide. Sun to part shade. Moist to dry, well-drained soil, preferably with a good amount of organic matter. Spreads slowly by rhizomes or seed. Bell-shaped, bluish violet flowers typically bloom through late summer. (pictured left)

◊ Gaillardia aristata (blanketflower): Perennial (short-lived). 1-3 feet tall x 1-3 feet wide. Sun to light shade. Tolerates a variety of well-drained soils; drought tolerant when established. Spreads by seed. Colorful yellow and reddish orange flowers bloom well into fall, especially when dead-headed. Deer resistant.

◊ Solidago canadensis (Goldenrod): Perennial. 2-4 feet tall x 2-3 feet wide. Sun to part shade. Solidago canadensisTolerates wide range of soils; prefers moisture but tolerates drought when established. Spreads by rhizomes or seed. Bright gold, fragrant inflorescences typically bloom well into fall. (pictured right)

◊ Symphyotrichum subspicatum (Douglas aster): Perennial. 2-3 feet tall x 2-3 feet wide. Sun to part shade. Does best in moist soil that is rich in organic matter. Spreads slowly by rhizomes and seed. Lavender-blue daisylike flowers bloom from mid summer until mid fall. (pictured below)

 

 

Douglas aster

 

 

© 2015 Eileen M. Stark

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Posted on by Eileen Stark

10 Great Northwest Native Pollinator Plants for Summer

Bombus vosnesenskii

In honor of National Pollinator Week, let’s zoom in on the bees and other hard-working pollinators whose lives are dictated by weather, season, and the availability of food, nesting habitat, and overwintering sites.

Nature has provided pollinators with unique ways of gathering nutritious pollen and nectar for their young, and they’re enthralling to watch. But bees and other pollinators are in terrible trouble worldwide due to our presence and actions. We can give back to them by growing flowering native plants in our gardens (as well as noninvasive exotics that are especially attractive to bees, like lavender and sunflower) with consecutive blooms from early spring till fall. But don’t forget to provide for them during all their life stages — not just their adult stage — by leaving the leaves, dead wood, and spent flower stalks to make sure they can get through the winter and have habitat to raise their young. And, no pesticides whatsoever!

If you’ve already included some native plants in your yard, you’re well on your way to providing for a wide variety of wildlife. Offering a variety of flower shapes, colors, and sizes, with smaller plants in groups of at least three of the same species (like a big, obvious “Eat” sign) will help provide for many different types of pollinators—from long and short-tongued bumblebees and syrphid flies to hummingbirds, beetles and thrips. Below are some Pacific Northwest native herbaceous perennials and shrubs that offer food for pollinators from early to mid or late summer in the Pacific Northwest, west of the Cascades.

The list is just a sampling (read about others in my book or within my blog’s PNW native plant profiles), and the species were chosen because they naturally occur in large parts of the region, are generally easy to grow, aren’t too hard to find at native plant nurseries (although you may need to call around for availability), and attract their fair share of native pollinators. I’ve listed them alphabetically with some basic care guidelines. Fall planting is best, as winter rains begin. (If you’re reading this in springtime, don’t worry—you can plant now, but you’ll definitely need to keep an eye on their water needs during the first couple of summers, at the very least.)

As always, plan ahead and choose plants that fit your light, moisture, and soil conditions, but also choose those that are appropriate to the natural landscape—that is, look to nearby natural areas and add flora that likely would have grown in your area historically. You can also search for a species’ natural range (to county level) here, or check with your local native plant society chapter or county soil & water conservation district. Growing them with associated species that evolved alongside them in nature will help them thrive. No fertilizer is necessary (although a one-time addition of compost such as leaf compost to the soil will add some nutrients and improve soil structure), but do keep them adequately hydrated until they’re established (2 to 5 years). Enjoy!

◊ Achillea millefollium var. occidentals (Western yarrow): Perennial. 1-3 feet tall x 1-3 feet wide. Sun to part sun. Not fussy about soil; moist or dry (will spread faster with more moisture). Spreads by rhizomes and seed. Flat-topped clusters of white, fragrant flowers bloom nearly all summer. (Not to be confused with the Eurasian Achillea millefolium var. millefolium).

◊ Asclepias speciosa or A. fascicularis or A. cordifolia (milkweed) : Perennial. 2-3 feet tall x 2-3 feet wide. Sun to part shade. Moist, well-drained soil, but can handle some drought when established. Rounded clusters of soft pink, fragrant flowers. Check out the Xerces Society’s info on milkweed of Oregon and of Washington. (A. fascicularis is pictured, right)Asclepias fascicularis

◊ Campanula rotundifolia (common harebell): Perennial. 1-2 feet tall x 1-2 feet wide. Sun to part sun. Well-drained, moist to dryish soil. Spreads slowly by rhizomes or seed. Bell shaped, violet-blue blossoms.

◊ Ceanothus velutinus (snowbrush): Fast growing evergreen shrub. 6-12 feet tall x 6-12 feet wide. Sun to part shade (intolerant of full shade). Rich or poor soil; very drought tolerant. Dense pyramidal clusters of tiny, fragrant white flowers. Occurs mainly at mid to high elevations; check natural occurrence, to county level, here.

◊ Erigeron speciosus (showy fleabane): Perennial. 2 feet tall x 2 feet wide. Sun to part shade. Well-drained, moist to dry soil. Lovely and abundant daisy-like, bluish lavender blossoms go nearly all summer. (pictured below)

Erigeron speciosus

◊ Holodiscus discolor (oceanspray, aka cream bush): Fast growing, very attractive deciduous shrub. 8-16 feet tall x 8-12 feet wide (larger on protected sites, smaller on windy, harsh sites). Sun to part shade (intolerant of full shade). Not fussy about soil; moist or dry. Drought tolerant when established. Lavish, feathery plumes of creamy-white flowers in early to mid-summer. Nice for hedgerows. Controls erosion.

 

◊ Lupinus polyphyllus (large-leaved lupine): Perennial. 2-4 feet tall x 2-4 feet wide. Sun to part shade (intolerant of full shade). Moist soil preferred but will tolerate short dry periods. Tall spikes of bluish-purple, pea-like flowers. (pictured, right) Lupinus polyphyllus

◊ Sedum spathulifolium or S. oreganum (stonecrop): Perennial. 1-4 inches tall; spreads slowly. Sun to part sun (afternoon shade is welcome). Well-draining, gritty, lean soil. Bright yellow star-shaped flowers. Nice for rock gardens. Not a ground cover for foot traffic. (S. spathulifolium pictured below)

◊ Symphoricarpos albus (snowberry): Deciduous shrub. 4-6 feet tall x 4-6 feet wide. Sun to mostly shade. Moist or dry soils; tolerates heavy soils. Drought tolerant when established. Tiny, paired, pink, bell-shaped flowers. Eventually forms a thicket. Controls erosion.

◊ Tiaralla trifoliata (foam flower): Perennial. 8-14 inches tall x 1-14 inches wide. Shade to part shade. Spreads very slowly by rhizomes or seed. Needs moist, well-draining soil rich in organic matter. Panicles of white to pale pink flowers bloom from late spring to late summer. More details here.

Sedum spathulifolium with syrphid fly

 

Copyright 2015 Eileen M. Stark

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Posted on by Eileen Stark

Pacific Northwest Native Plant Profile: Bear Grass (Xerophyllum tenax)

X. tenax up close

When I mention bear grass, people familiar with the plant usually light up as if its creamy blossoms were right in front of their face. I’m lucky to have one in full bloom right now in my backyard (yes, just one—I have more, but they’re too young to bloom). Bear grass typically takes many years to flower, so I am savoring this one as much as possible. En masse in nature they are quite a vision, and even when not in bloom they make a lovely, luminescent, soil-stabilizing ground cover. But don’t you dare even think about taking even one plant from the wild.

X. tenax on Larch MountainBear grass, a common name for Xerophyllum tenax, comes from observations that bears like to eat the young fleshy stems, and Grizzly bears reportedly have been known to use bear grass leaves in winter dens during hibernation. It’s a popular plant for many other species who use it for food or cover: from bees and beetles to rodents and elk. Though not a true grass, other common names include Indian basket grass, deer grass, elk grass, and soap grass (not sure where the latter came from!).

The botanical name comes from the Greek xero (dry) and phyllon (leaf), and the Latin tenax (tough or tenacious). It’s an evergreen member of the corn lily family (Melanthiaceae), a group of flowering perennial herbs native to the northern hemisphere. I’ve included bear grass in my book even though it’s not terribly easy to grow. When it does establish, it spreads (very slowly) by forming offsets and by seed.

Long, skinny, and rather wiry leaves arise from the rhizome in clumps. Their edges are rough and finely serrated and it’s their toughness that helps the plant minimize water loss during periods of drought, as well as insulate it from frost.Xerophyllum tenax (foliage)

Flowers open from the bottom up, so that the inflorescence, which ranges in height from two to five feet, takes on many different shapes as it matures. Flower fragrance varies; one study reported that one-fifth of bear grass flowers in their sample had a sweet smell like cultivated lilacs, while the others smelled “musty-acrid.” The one now blooming in my yard is, thankfully, the former, although not as sweet as lilacs.

After the blossoms fade away the flowering plant usually dies, but the long-lived rhizome lives on and offsets bloom when they are mature enough. Its fruits are three-lobed dry capsules, about ¼ inch in length, that contain 6 or 7 beige seeds, which may be eaten by migratory birds prior to fall flights. They may be sown in late summer, fall or winter and need at least 12 weeks of cold stratification.

How it grows
Bear grass grows naturally in a variety of conditions—in cool, moist meadows and bogs, and mixed-coniferous forest openings in most of western Washington and Oregon, coastal areas of northern and central California, northern Idaho, parts of British Columbia and Montana, and a snippet of Wyoming. I’ve come X. tenaxacross it on hikes in the Oregon Cascades near trees such as Douglas-fir, Western hemlock, or mountain ash, and among smaller species like huckleberry, bunchberry, fawn lily, star-flowered false solomon’s seal, inside-out flower, foamflower, and woodland strawberry.

It’s often found growing on slopes (in soil that’s not particularly rich) that are moist during winter and spring, but fast draining. I grow mine on a south-facing slight slope, in partial shade. The soil’s a bit rocky and has been amended with leaf compost. Large rocks nearby help keep roots cool and moist. During very warm and dry periods I give supplemental water, especially when plants are young.

Conservation

For centuries, Native Americans valued bear grass and used it sustainably for basketry and decoration, and ate the roasted roots. Today bear grass is having a very tough time surviving with our myriad modern threats: Logging and other habitat loss, introduced forest pathogens and insects that affect associated species, fire suppression, and the floral industry that recklessly collects it for lucrative commerce (much of it is exported). If you know of a florist who uses bear grass, ask them where they got it and explain the disastrous ramifications if necessary. Never take this plant (or any other native plant) from the wild.

Bear grass is a fire resistant species that is often the first plant to grow after a fire. Like many other native plants, it needs periodic burns for strong new growth. Following a light fire that increases light, growing space, and soil nutrients, bear grass sprouts from its rhizomes, which lie just under the soil’s surface. But when fires are suppressed—often due to timber industry management—the result is fewer but much more intense fires that kill rhizomes, making it impossible for the plants to come back.

X. tenax closeWildlife value
All of these perils affect not only the species directly, but also its pollinators—nearly 30 species of flies, beetles, and bees, and possibly some butterflies, moths, and wasps. Besides pollinators, bear grass also provides food for rodents, deer and elk, and even mountain goats at higher elevations, as well as other habitat components, such as nesting material for birds, mammals, and insects—all of which are essential, interconnected ecosystem members. More info on conservation here.

Beargrass’s only close relative, X. asphodeloides, grows in the southeastern part of the U.S.

 

© 2015 Eileen M. Stark

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Posted on by Eileen Stark

The Beauty of Fawn Lilies (Erythronium spp.)

Erythronium oregonum

The genus Erythronium, commonly known as trout lily, fawn lily, glacier lily, or dog-tooth violet (depending on the species and your location) offers such elegance that I can say with conviction that it is my favorite spring wildflower. Single plants charm and invite close scrutiny, but when found in drifts their collective luminescence completely captivates me. Let their magic entice you, too.

About 20 species of Erythronium are found worldwide and most occur in the western U.S. The botanical name comes from the Greek Eruthros, which means red, and refers to the pink or reddish flowers of some species. The photos in this post, which I took in my garden, show the pagoda-like flowers of Erythronium oregonum (Oregon fawn lily or giant white fawn lily), which naturally occurs in moist to dry woodlands and grasslands at fairly low elevations in southwestern British Columbia and Washington and Oregon (west of the Cascades), as well as parts of northern California. No doubt the Georgia Basin, Puget Trough, and Willamette Valley were once thoroughly adorned with them.

What appear to be recurved petals are technically tepals (a term used when petals and sepals cannot be differentiated)—white to pale yellow, with a gold heart in this species. Paired leaves that hug the earth are oblong and mottled, and gorgeous on their own. The only downside of this native plant is its ephemeral nature: Like most perennial bulbs, it goes dormant in summer. But when the flowers fade away in my low elevation garden, I know I can always venture to a higher elevation and find it, or a closely related species, quietly in bloom a month or two later.    E. oregonum

How it grows
Pollinated by native bumble bees, butterflies, moths and hummingbirds, this endearing plant thrives in partial shade (but not deep shade) with well-drained, slightly acidic soil that’s rich in organic matter—imagine the dappled shade of an open forest or wooded grassland where fallen leaves and other organic matter are allowed to accumulate. That said, I have several growing where they get very little direct sunlight and they appear quite happy, blooming each year (although not prolifically). They’re also found naturally in rocky areas, so look lovely planted in partly shaded rock gardens where their bulbs can stay cool during summer.

Try it at home
Though not a true lily, Erythronium species are easy to grow and trouble-free, as long as you are aware of their needs. If your yard is lacking rich topsoil, add well composted leaf mold before planting and don’t remove light layers of fallen leaves from the top layer of soil. Bulbs should not be allowed to dry out completely, but they may rot with consistently moist conditions, so be sure they’re placed where the soil drains well. Keep soil just slightly moist during the dry summer months of the Pacific Northwest.

They look best grown en masse, as found in nature. Plant them at the same depth (or slightly deeper) that they came in their pots, or about three to four inches deep. The bulbs are extremely delicate, so don’t try to move them after they are planted unless you can dig up a big chunk of surrounding soil without disturbing the roots, bulb, and stem in any way.

As far as propagation goes, bulb division in your garden is possible but not recommended—if they are planted in appropriate conditions they will sow themselves. Or, you can help them along by collecting seeds from their capsules after the seed has ripened and the flower scape splits; I once shook out 50 seeds from one dried flower capsule! You can sow the seeds immediately outdoors if they are dry enough, or keep them in a cool, dry place and wait until late summer to sow them (but don’t wait much longer, as they reportedly do not keep well): Fill a deep container or pot with a well-draining soil mixture. Press the seeds onto the soil and cover with coarse grit, then leave them outdoors to expose the seeds to cold/wet of winter. In springtime they will germinate and a single cotyledon will emerge. The second year, a single leaf will grow. Carefully separate the tiny plants during the end of the second or third summer (no earlier), repot, place in a bright, cool location where the plants can be kept moist during winter and spring and just slightly moist during summer. Patience is needed, though—it can take as long as five years until first bloom. Some species will multiply vegetatively if the flowers are carefully removed soon after flowering, which prevents energy going into seed production and instead into making more bulbs underground. If you have optimal conditions, you may find that they will self sow around your garden.  (2022 UPDATE: Six years after this post was written I can say with confidence that these lovely plants have indeed sowed themselves around my mostly native back yard.)

Grab a partner
E. oregonum can be found growing with other natives such as Garry oak, (Quercus garryana), Oregon ash (Fraxinus latifolia), oceanspray (Holodiscus discolor), snowberry (Symphoricarpos spp.), sword fern (Polystichum munitum), camas (Camassia spp.), and various native grasses. Placing them under deciduous trees that allow early spring sunshine to nourish them but provide protection later on is optimal, but be sure not to plant them where some leafy, overly zealous understory plants will cover their leaves during spring (such as western bleeding heart)—I learned that the hard way. Substitute fawn lilies for bulbs like invasive Spanish bluebells that seem to be in almost every yard in my neighborhood.

Some related species: Erythronium revolutum (pink fawn lily) occurs naturally in moist coastal forests near shaded streams and in bogs; it is a “species of concern” in Oregon. A higher elevation species is E. montanum (avalanche lily, white avalanche lily) that is native to coastal B.C. and alpine and subalpine Olympic and Cascade ranges. Erythronium grandiflorum, or glacier lily, with gorgeous yellow flowers, is also found in alpine and subalpine meadows and does best at those elevations. E. hendersonii (Henderson’s fawn lily) occurs at low to mid elevations in the Siskiyou Mountains of southwest Oregon, while E. elegans (Coast Range fawn lily) is a threatened species that grows only at high elevations of Oregon’s Coast Range.

Enjoy! But please … never collect Erythronium seeds or plants from the wild.

E. oreganum

 

 

© 2015 Eileen M. Stark

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Posted on by Eileen Stark

A Native “Shamrock”: Oxalis oregana

Oxalis oregana

Happy St. Patrick’s Day!

The shamrock legend can be traced to the 5th century saint who used a three-leaved plant—possibly white clover (Trifolium repens)—to demonstrate the concept of the Christian trinity. Today, oxalis cultivars, or any plants with tripartite leaves labeled as shamrocks, are sold as houseplants or outdoor plants.

Our Pacific Northwest native Oxalis—sometimes called wood sorrel—is a beautiful ground cover for mostly shady areas (but also more open, shrubby areas) at low to middle elevations. It has edible leaves high in oxalic acid (like spinach), and forms a lush carpet in moist to dry woodlands.

Three wood sorrel species that occur naturally in the region are Oxalis oregana (wood sorrel or Oregon oxalis), O. suksdorfii (western yellow oxalis, which occurs mainly in southwestern WA and Oregon at low elevations), and O. trilliifolia (trillium-leaved oxalis). When deciding which species to grow, pick one that naturally occurs in your area (see map links in previous sentence).

Wildlife value
Oxalis is a pollinator plant, offering its charming small flowers to native bees, syrphid flies, and butterflies. Like most flowering plants that grow under low light conditions, its blossoms are white or light colored to enable pollinators to be able to easily see them. Later in the year, Oxalis seeds may be eaten by seed-eaters like sparrows and small rodents. Its leaves serve to protect and enrich the soil.

Try it at home
Grow it in the shade of tall trees like Douglas fir and with other native woodland species such as Vaccinium spp. (huckleberry), Mahonia nervosa (Cascade Oregon grape), Gautheria shallon (salal), Polystichum munitum (sword fern), Prosartes spp. (fairy bells), Trillium ovatum (western trillium), and others.

Give it moist, acidic soil (pH 5 to 6.5), preferably rich in organic matter. While morning sun is welcome, it typically won’t do well with scorching midday or afternoon sun. In full shade and once established, it is a drought tolerant plant. Be sure you like it, though, because it will spread—enthusiastically, in the right conditions—to protect the soil and soil dwellers.

Oxalis oregana

 

© 2015 Eileen M. Stark

To leave a comment, click on blog’s title
Posted on by Eileen Stark