By Sean Hogan
Hundreds of drop-dead gorgeous plants native to the
West—that will thrive in our gardens—are available with only a little
searching. Recently there has been a renewed interest in natives, given
concerns about water use and an inclination to tread more lightly on our
planet. We gardeners can have the best of both worlds: feeding our gluttonous
desire for beautiful plants—and honoring the environment.
The following are a few native groundcovers and
low-growing shrubs to consider. First, the smallest.
Perennials & Groundcovers
is a favorite seen in many old gardens—though some forms are feared as
spreaders. This little “clover” is wonderful for massing among shrubs and
trees. I prefer the evergreen forms from the coast, particularly two favorites.
The first, Oxalis oreganum
f. smalliana, which I
received from Portland’s Leach Botanical Garden, is six inches in height with
silver-splashed leaves and large pink flowers. The other, I found on the
southern Oregon coast, and is named Oxalis
oreganum ‘Klamath Ruby’. It grows eight inches tall, the leaves have
a burgundy reverse, and it produces white to pale pink flowers. Both are
perfect in the deepest shade, often growing through winter and able to take
long periods of summer drought—only wilting in the heat of the Willamette
Pacific coast iris are regaining a foothold in local
gardens now that their needs are better understood. Like other natives, they
prefer pretty lousy soil, perfectly gritty (though clay works), and little
summer water especially when heat is involved. They are divided in late fall
when the season’s roots are beginning to emerge. Iris
tenax, a native from southwestern Washington through the Willamette
Valley is often seen in shades of purple, pink, and white. It is the only
species to be partially deciduous.
Others, like Iris
innominata of the Siskiyous, often bring shades of yellow and orange
into the mix. Iris douglasiana,
found from the central Oregon coast southwards in clumps to three feet tall,
has substantial evergreen leaves and blue to white flowers from March to June
depending on its location.
Asarum, or wild gingers, are not as numerous in
western North America as in Asia but the few we have are both beautiful and
vigorous. Asarum caudatum,
with its heart-shaped, evergreen leaves is useful in dry shade, spreading in
time to large ginger-scented patches.
hartwegii, another Siskiyou resident, grows in shade and—surprisingly—in
sunny, inhospitable places, offering a color and texture as close as we can get
to cyclamen. Its heart-shaped, silver-streaked leaves sometimes take on a
reddish cast in winter. The flowers are black and held on the ground to be
pollinated by crawly things. Slow to spread into compact clumps, A. hartwegii should
every few years.
The Shrubby Natives
More and more manzanitas are becoming available. One
in particular has been outstanding
in my garden: Arctostaphylos
pajaroensis, endemic to a small area between Monterrey and Santa
Cruz. It grows to three or four feet tall and is one of the most attractive
winter-flowering plants available. Its open habit displays cherry red stems
with peeling bark around which are clasping, eucalyptus-like blue-green leaves
often flushed pink with spring’s new growth. The cultivar A. p. ‘Warren
out in midwinter flowers of a cheery pink.
A number of my favorite low shrubs are in the genus Ceanothus.
Ceanothus gloriosus ‘Point
Reyes’ is a native with gray-cast leaves. It has pale blue flowers on plants
under a foot tall but spreading to four or five feet wide.
A somewhat daintier plant, the variety porrectus
(C.g. var. porrectus)
and specifically the
cultivar ‘Emily Brown’ grows to 18 inches tall as a more rounded low shrub with
small, dark green leaves and flowers the color of a blue June sky. A relative, C.
rigidus and its cultivar
‘Snow Ball’ is only slightly larger with a clean white flower against silvery
leaves in spring—wonderful with such neighbors as rosemary or a dwarf
The small form of our coastal native C. thyrsiflorus var. repens,
which remains under three feet in height, spreads gleefully over walls or stray
basketballs hidden in the garden. It’s a little shy to flower, but when it does
it’s covered in a solid amethyst-blue blanket offset by shiny one-inch leaves.
In gardens where temperatures are likely to fall to 10° F or below, it should be used sparingly. Another great low-growing
x ‘Centennial’, is of about the same hardiness,
remaining under 18 inches in height but spreading—well—pretty much forever. It
has curled, shiny leaves and deep blue flowers. It’s my favorite ground
covering ceanothus. I have it planted where Amaryllis belladonna emerges through it in
Our native coyote bush, Baccharis
pilularis, found in various forms from Astoria to Baja and
inland in places in the Willamette and Sacramento Valleys, ranges from large
shrubs to petite groundcovers. The cultivar ‘Twin Peaks’ has small leaves and
grows slowly to two feet, spreading to around five feet. One of my selections,
‘Creeping Green’, found on the central Oregon coast, reaches three by five
feet. It produces creamy yellow flowers in winter and again in early summer, a
draw for needy pollinators.
The buckbrushes, or Rhamnus,
come in several small forms, including Rhamnus
californica. New on the scene, and given to me by Rancho Santa Ana
Botanical garden, is R. californica
‘Leatherleaf’. It has a nearly black-green appearance and, so far at least, a
height of less than three to four feet. (If I’m wrong, please get back to me.)
There seems to be great fear of the Oregon grape, Mahonia
because of its overuse in highway medians where it never looks happy.But other
species are well worth growing. Mahonia
nervosa is used as a delicate, 18-inch groundcover. Another I’m
quite enamored with is M. dictyota
with blue-green leaves, a dense rounded habit to three or four feet, and
extreme drought tolerance. Its early spring flowers, emerge from peach-hued
buds. One word of warning: it’s a bit vicious as each “lobe” is armed with a
These are just a few examples of low-growing natives that
are an asset to any Northwest garden. Some are increasingly available at
nurseries, including the California lilacs (Ceanothus).
A visit to regional botanical gardens or nurseries will turn up some of the
above. The next time you encounter one of these attractive and practical plants, take
it home with you! NWGN
Sean Hogan collects drought-tolerant plants
for his nursery, Cistus Design Nursery, in Sauvie Island, Oregon,