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

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

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 common and 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), 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.

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

Green Corridors Begin at Home

“Is the deer crossing the road, or is the road crossing the forest?” 

To survive, most wild fauna must be on the move—to find food, water, safe shelter and breeding sites, mates, and, for some species, to migrate. But wildlife habitat is increasingly destroyed, degraded, or fragmented into small, isolated patches—by human-made barriers such as buildings, fences, lawns, and roads—which intensify their struggle to survive.

Habitat loss is one of the main threats to wildlife. More people and development mean less natural habitat, while inaction on the climate crisis forces animals to relocate. Today, more than ever, habitat connectivity needs to be restored and wild ones’ daily and seasonal movements or migrations protected.

Habitat connectivity is defined as the degree to which the landscape helps or hinders animals’ movements, as well as other ecological processes, such as seed dispersal. Whether they’re called conservation corridors, green corridors, habitat corridors, or wildlife pathways, their purpose is identical: To provide native habitat as seamlessly as possible, so that wildlife populations may be connected instead of separated. Even in deteriorated landscapes, such corridors boost biodiversity, allow genetic exchange between populations, and may even help ease the reestablishment of populations that have been decimated, isolated, or previously extirpated.

Recognizing that every front, back and side yard—even those within urban areas—is part of an intricate ecosystem that could support a great number of species is the first step toward encouraging rich, natural diversity. When “real” or “naturescaped” yards link directly to others like them, they help mitigate some of the effects of fragmentation, a huge threat to biodiversity. In general, urban and suburban areas are highly fragmented. Wildlife corridors are essential, especially for animals with large ranges.

You might be wondering, “Aren’t large-scale habitat connectivity projects happening?” or “Isn’t my yard too small to help much?” Yes, and no: The big projects are vital and projects such as underpasses and overpasses that help wildlife cross busy roads (that kill or injure many millions of animals each year) are multiplying, thanks to recent legislation in some states, as well as the federal Wildlife Crossings Pilot Program that provides funding. But also crucial are all the little spaces that—even if they’re not in the path of pronghorn or monarch butterflies—when added up, create interconnected networks. As I wrote in my book, “To be most beneficial, gardens need to connect—to each other and to the larger world—to provide continuous passage for wildlife and allow each garden to work and blend harmoniously with others nearby. A single naturalistic garden has benefits, but when in proximity to others like it, its worth multiplies.” Studies show that “the role of corridors is crucial for enhancing biodiversity in green spaces such as domestic gardens … results clarify the effectiveness of corridors in urban landscapes and have direct implications for the ecological management of cities.”

What to do? Whether you’re an avid gardener or someone who cares about dwindling wildlife, you can take positive action to help your property, balcony, or communal green spaces act as safe stepping stones within a green corridor that supports wildlife. It’s something that we can do despite (or perhaps because of) the heinous weakening of environmental protections by certain politicians over the past few years. And, it’s effective, rewarding, and usually fairly easy if you plan ahead.

Some basic tips:
Grow a diversity of locally native plants, and be sure to remove exotic invasive plants as much as possible beforehand (incrementally if they are used by wildlife). Your yard doesn’t have to be exclusively native, but when planted appropriately, the trees and shrubs that evolved in your area are especially important for supplying food, shelter, and possibly nesting sites.

Don’t fence them out (or in). When we moved into our house, one of the first things we did outdoors was remove two gates to our backyard. They served no purpose and I wanted to make it easy for four-legged fauna to come and go. While there are situations where fencing is helpful (for a dog run, to protect a veggie garden, or to prevent a little one from wandering off), many urban and suburban back yards are separated by tall, unattractive fencing that does nothing useful except provide some privacy.

Instead of impassible fencing (that also greatly diminishes air circulation around plants and, in the case of wooden fencing, wastes trees), think living, breathing native shrubs—either in an unpruned hedgerow or more naturalistic plantings—to provide privacy. Besides being much more aesthetically pleasing, shrubs alone provide food and shelter for wildlife, shade and carbon sequestration, and contribute greatly to green corridors. Unlike fencing, shrubs provide privacy but allow small animals to pass under, through, or along, from garden to garden. If your yard is tiny and you must add a narrow barrier, consider wooden lattice fencing with large openings, upon which (noninvasive) vines could grow (but don’t do this if you live where megafauna could get caught in it).

Some types of fencing can brutally kill or ensnare wildlife (and even people), often at nighttime. Avoid metal rail fencing, any spiked fencing, and all plastic netting. When not in use, take down volleyball and soccer netting.

Rethink manicured yards. Highly pruned, overly tidy, leafless, lawn-centric yards sustain very little life and are high-maintenance. Instead, create a chemical-free native wildlife garden that is more relaxed (some might say “messy”) and has the ability to support much more life. If you’re worried about what the neighbors will say, add some signs of human intention in the front: (a) Create interesting structure by varying the heights of plants so there is a connection from tall trees to ground cover—this not only looks nice, it’s great for wildlife; (b) Choose shrubs that can grow to their full potential without crowding each other out, hiding your doors or windows, or encroaching into pathways—all of which will eventually require harsh pruning; (c) Instead of one plant here, one plant there, plan for a rhythm by growing perennials in drifts or uneven clusters, and then repeat them elsewhere in your yard (this is also highly beneficial to wildlife like pollinators who need multiple plants to feed on); (d) Consider adding step stone paths, bird baths, strategically placed half-buried rocks, sculpture, or nest boxes (if appropriate), but don’t overdo it—few “focal points” are better than many. Don’t add landscape lighting, which is deleterious to living things.

Avoid “ecological traps” and minimize danger. When we grow native plants, minimize lighting, leave the leaves, add a water source and other positive elements to our yards, one of the wonderful outcomes is the increase in wild visitors. But no matter how well-meaning our actions are, “ecological traps” may be created when we make our yards welcoming to wildlife but don’t address the human-induced hazards that lurk nearby. When we design for biodiversity we must consider not just adding habitat, but also what we might inadvertently set them up for, such as being preyed upon by cats or dogs, or injured or killed by windows or some other hazard in our yard. Of course we don’t want to eliminate windows or companion animals, so we have to embrace adaptations that allow us to keep them and protect wild ones at the same time.

In other posts I’ve addressed the disastrous effect that reflective windows have on birds as well as the consequences of light pollution. Another lethal issue is free-roaming cats. Certainly not all cats are avid hunters, but many are, and it’s up to us to take responsibility for their actions. If you already have a kitty who’s been spending a lot of time outdoors, it’s going to be difficult—or even cruel—to suddenly lock him up and throw away the key. Cats are obligate carnivores, so it’s not their fault that they hunt, or want to. For those with unbreakable habits, consider limiting outdoor adventures during baby bird season (late spring to mid-summer) and at those times of the day when birds are actively feeding (typically early morning and late afternoon), and use hanging birdbaths instead of grounded ones. The next time you adopt a new cat, keep them safely indoors but offer a place to get fresh air, like a catio. Dogs, of course, may also be problematic, especially in areas where sensitive wildlife live or nest on the ground, such as fragile amphibians and reptiles.

Minimize hardscape. Unnatural hardscape does nothing for wildlife. Every time we remove hardscape and replace it with, say, regional native plants, dead wood, a water source and other beneficial elements, we help wildlife thrive. Minimizing it in your yard also helps reduce stormwater pollution, improve water quality, and mitigate the impacts of climate chaos.

Urge urban planners and park space advocates to plant native species. Despite native plants’ benefit to ecosystems and humans, they aren’t often added. A typical city park, for example, contains large expanses of lawn and some isolated trees (often non-native). Ecosystems are much more complex and may include tall trees, smaller trees, large and small shrubs, perennials and grasses, dead wood and fallen leaves, which support a large number of species. Creating native beds surrounding single trees, or at least within designated areas, will add complex layers without eliminating picnic space.

Finally, talk with your neighbors. Imagine if everyone’s yard was connected—botanically speaking—to the one next door, preferably without fences and gates. Then imagine that these connections continue from neighborhood to neighborhood and go on for miles, finally reaching a large natural area that’s even more supportive. Some neighbors may find your ideology beyond their grasp, but others may surprise you. Some people simply may not know about the deadly hazards of development and exotic plants, and speaking with them—or at least setting an example—may help to open their eyes and hearts.

 

© 2020 Eileen M. Stark

Just the Thicket … For Wildlife Habitat


If you’re looking for ways to counteract — in a small but significant way — the relentless destruction of the natural world and want to turn your yard into a place that supports the wildlife community, or you already garden for biodiversity, you probably know that appropriate habitat — food, water, space, cover — is essential. Food is best supplied by regional native plants that produce insects, nectar, pollen, fruit, and/or seeds, while water comes either from natural sources or human-made birdbaths or ponds. Adequate space is important to prevent competition for food, cover, and nesting sites. Cover, or shelter, is as crucial as the others because wild fauna need places that not only shield them from inclement weather, but also hide them from predators (and people). Predatory animals themselves often need cover to successfully obtain prey. A lack of cover is a limiting factor for many wildlife populations.

Increased biodiversity comes with careful planning and placement of cover habitat supplied both vertically and horizontally with small and large native shrubs and trees. Those with particularly dense foliage may also provide valuable nesting habitat, as well as privacy for you, or even a windbreak if strategically placed.

Thickets are a great way to provide cover for relatively small animals, due to their tendency to be impenetrable to large species. They may be dense groups of trees or shrubs, usually dominated by one or a few species that tend to be multi-stemmed and often densely twiggy, or they may be formed by a single species that either enlarges via underground suckering stems or sheds large numbers of seeds that have the ability to grow beneath or close to the parent plant. Thickets of the latter type may also be spread by human disturbance. 

Even when leafless, red-twig dogwood (Cornus sericea) attracts birds.


Because thickets tend to fill quite a bit of space, they usually are not suitable for very small gardens, since they will tend to “take over” a small space, either fairly quickly or over many years, depending on the species. But if you have a fairly large yard or an acreage, native thickets create mini-ecosystems within which essential food and cover are supplied for a large number of beneficiaries, from insects and birds to reptiles, amphibians and mammals, depending on the location. They’ll also conserve soil moisture and may slow — or even prevent — erosion on slopes. And, when well established, thickets keep out many invasive weeds (note: always remove weeds well before planting any type of native plants). Many of these plants also can provide food for us, but I suggest you share with wild visitors.

Thickets often get a bad rap because they don’t look particularly neat and orderly, but if you garden for wildlife you know that messy and naturalistic is much better for the wild ones. To tidy up shrubs that tend to develop into thickets, gardeners often clip out suckers and sprouts for appearance’s sake, but that’s to the disadvantage of wild visitors.

Pollinators love thickets!

Although thickets (especially thorny ones) may not be suitable for most front yards, in back yards or other areas, they can be wonderful wildlife magnets. And when located as far from human activity as possible, they also lend tranquility in an urban environment. Though my yard is just one sixth of an acre, I have several thickets—one that’s composed of snowberry and clustered rose, several of tall Oregon grape, and a large clump of thimbleberry. It seems there’s almost always something going on: A little bird or two flitting around branches looking for food, a ground feeding bird foraging within fallen leaves, pollinators hard at work, or — during nesting season — a bird vocally establishing his territory. Flowers’ pollen and nectar attract a variety of native pollinators in springtime, fruits or seeds become available later in the year, and the rose offers a place for mourning cloak butterfly larvae to develop.

Choosing thicket species
In nature, thicket-developing plants grow in forested areas, as well as open areas such as historic savannas (a grassland with trees scattered at least 100 feet apart), upland prairies (another type of grassland) or wet prairies. Needless to say, savanna/prairie plants require more sunlight than forest thicket species. Since humans have converted most savanna and prairie habitat to agriculture and livestock grazing, those thicket species aren’t having an easy time; they’re mostly forced to live on forest edges and fence rows and are threatened by invasive species.

Prairie or savanna thickets naturally would be surrounded and complemented by native herbaceous plants and grasses that are members of a plant community, which together would create a highly supportive ecosystem. Forest species also would naturally occur with ‘associates’ that interact and flourish together.

Thorny native thickets, such as this Rosa pisocarpa, offer a place for birds to rest as well as forage.


Here are some plants that typically will form thickets in the Pacific Northwest, west of the Cascades (but it’s not an exhaustive list). Choose species that would naturally occur in your area; check native status to county level here.

For sun to part sun: Douglas hawthorn (Cragateus douglasii), Red-twig dogwood (Cornus sericea), California hazelnut (Corylus cornuta var. californica), Western crabapple (Malus fusca), Western serviceberry (Amelanchier alnifolia), Ninebark (Physocarpus capitatus), Tall Oregon grape (Mahonia aquifolium), Bitter cherry (Prunus emarginata var. mollis), willows such as Salix scouleriana, S. lucida, S. hookeriana, and S. sitchensis, red-flowering currant (Ribes sanguineum), wild roses (Rosa nutkana, R. pisocarpa), Douglas spiraea (Spiraea douglasii*), white spiraea (Spiraea betulifolia var. lucida), Thimbleberry (Rubus parviflorus*), Salmonberry (Rubus spectabilis*).

For part shade to shade: Red elderberry (Sambucus racemosa), Snowberry (Symphoricarpos albus), Osoberry (Oemleria cerasiformis), Salal (Gautheria shallon).

* may spread rapidly.

Fox sparrow foraging beneath a thicket stays safe.



© 2020 Eileen M. 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 cover.

Mature size varies from around six to ten feet tall; width is typically similar, so do allow it enough space. 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 five 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 via self-sown seed, which are easily dispersed by birds or fall to the ground below. If you want to 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 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

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

Arbutus menziesii bark

Though 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.

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, 2023: At around 8 years of age, Ms. Madrone is now nearly 12 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 they have dried, soak them overnight to help release the seeds from the pulp). Place them 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, 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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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 designation as unofficial 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 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. 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.

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, fairybellsfoamflower, trillium, and many others.


© 2016 Eileen M. 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 (25-50 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 60 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 don’t use those watering 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 areasHere is more info on how to plant Oregon white oak.

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

 

© 2017 Eileen M. Stark

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Manage Stormwater at Home for Clean Rivers and Habitat

rainwater mitigation with trees

It’s another one of those exceptionally rainy days (with more to follow) and I don’t want to do laundry or even take a bath. Why? A few days ago the city’s sewers overflowed into the river, and I’d rather not add more water to an already overtaxed system that results in raw sewage killing and polluting the habitat of wild species downstream. It’s not just the abundance of rain that’s the problem: It’s our infrastructure.

Generally, the unaltered earth is perfectly capable of soaking up or directing the moisture that nature doles out to natural waterways or floodplains, and seasonal flooding is normal and natural. But our urban and suburban environments, with their ubiquitous, impermeable roads, walkways, roofs, and parking lots—as well as shortage of erosion-controlling plants—cause runoff that carries soil and toxic pollutants like oil, fertilizers, and pesticides during heavy rains. In older parts of cities, pipes and tunnels that take away domestic and industrial waste combine with water collected from surface runoff. Under normal (not too wet) circumstances, the sewage and runoff is diverted to sewage treatment plants. But when too much storm water or snowmelt can’t soak in, it overwhelms the system, creating combined sewage overflows (CSOs) that cause raw sewage and other pollutants to spill into rivers, lakes, or coastal waters. People may be told not to have contact with the water, but wildlife has no choice and suffers silently. Eventually, polluted sediment builds up in waterways, increasing water temperature and turbidity and lowering oxygen levels, resulting in deaths.

In Portland, where I live, the city is investing in stormwater management projects that (sort of) mimic nature, in an attempt to mitigate stormwater at its sources. There is a plethora of work going on and CSOs are reportedly decreasing in frequency, but even one is too many.

How to help keep water clean

We can help manage and reduce stormwater pollution and overflows, starting at home. Here are some tips; some will have immediate effect, while others will take some time and effort:

Protect existing conifer trees and plant new ones (preferably native species that historically grew in your area). A mature evergreen tree can intercept more than 4,000 gallons of rainwater each permeable hardscapeyear, quite a bit more than deciduous trees. They also provide habitat, beauty, shade and cooling and help stabilize soil. Don’t prune out lower limbs unless it’s absolutely necessary.

Renovate or construct new walkways, driveways, and patios with permeable paving, rather than concrete or asphalt.

Disconnect your home’s downspouts when feasible and install rain gardens or swales in landscaped areas. They help prevent flooding by allowing water that falls on your roof to slowly infiltrate into the ground, lessening the burden on sewer systems when it is most important. Simply disconnecting spouts and allowing water to run down a driveway or walkway and into the street defeats the purpose. Additional rain garden guides: here and here.

swale from disconnected downspout Use only organic fertilizers when necessary (excess can be washed into waterways), and don’t use pesticides.

Grow native plants that help control erosion. Some examples (that naturally occur in many parts of the Pacific Northwest) include vine maple (Acer circinatum), madrone (Arbutus menzeisii), Oregon white oak (Quercus garryana), oceanspray (Holodiscus discolor), serviceberry (Amelanchier alnifolia), salal (Gaultheria shallon), nootka rose (Rosa nutkana), sword fern (Polystichum  munitum), kinnikinnick (Arctostaphylos uva-ursi), and inside-out flower (Vancouveria hexandra). Choose plants that will fit your light, soil, and moisture conditions.

 Employ rain barrels to collect rainwater runoff from building roofs for irrigation during dry weather (if you can’t disconnect a downspout).

Conserve water simply by taking very short showers, never letting the faucet run unnecessarily, and fixing any leaks (just as you would during droughts!).

Collect “graywater” and use it onsite to reduce sewage discharges year round. Beware: this takes some ingenuity and planning!

 Never dispose of chemicals (like anti-freeze) by pouring it on the ground or into storm drains. Even drops of oil that seem relatively contained in your driveway can easily be swept into local waterways by rain. If you get an automotive oil leak, catch the oil in a pan and get it fixed ASAP.


© 2015 Eileen M. Stark

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