Pacific Northwest Native Plant Profile: Foamflower (Tiarella trifoliata)

           Tiarella trifoliata var. trifoliata    

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

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

Tiarella close-up

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

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

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

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

 

© 2016 Eileen M. Stark

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10 Great Northwest Native Pollinator Plants for Summer

Bombus vosnesenskii

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

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

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

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

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

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

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

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

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

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

Erigeron speciosus

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

 

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

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

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

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

Sedum spathulifolium with syrphid fly

 

Copyright 2015 Eileen M. Stark

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