CORVALLIS, Ore. – Groundcovers that spread across open areas and subdue weeds are even more effective if they are native to the area. Those that grow naturally west of the Cascade Mountains work great in local home landscapes.
Groundcovers are well known as weed suppressors, said Linda McMahan, native plant specialist with the Oregon State University Extension Service. But they also help the soil retain water and protect against soil compaction by keeping foot traffic away.
"As long as you locate them in your garden according to their taste for sun or shade, you shouldn't have to pamper them," she said. "And since native plants have co-evolved with deer and other wildlife, they are less likely to be wiped out by a marauding neighborhood doe."
McMahan has several suggestions for northwest gardeners looking for natives to plant.
For sunny areas, she likes coastal strawberry (Fragaria chilioensis), which has dark-green leathery leaves with white flowers in the spring and tiny fruit in the fall. She also recommends F. virginiana, a Willamette Valley native, for sun and part sun. F. vesca is shade-loving and also good for partial shade.
Kinnikinnick (Arctostaphylos uva-ursi), a low-growing favorite evergreen, has tiny glossy leaves and reddish woody stems. Most of the kinnikinnick on the market is labeled "Massachusetts," and is not native here. The northwest native kinnikinnick can sometimes be found at a native plant nursery.
Western bleeding heart (Dicentra formosa) likes shade, dies back to the ground in the winter and by mid-spring grows about 18 inches with hanging clusters of pink flowers.
Another shade-loving native is the inside-out flower (Vancouveria hexandra). About a foot high, it has small light-green leaflets and looks similar to ivy. "It's a great groundcover," McMahan said. "It turns a beautiful yellow in late November and December and re-emerges the next year." Although native to coastal forests, it's also partially drought-resistant. It spreads slowly and its roots form a dense mat.
Wood sorrel (Oxalis oregana) spreads by rhizomes and grows to about 10 inches high. It has light-green, three-lobed foliage and white-to-pink flowers in the spring. It grows well in shade and in colder areas dies back in the winter. If it doesn't, you may want to mow it to force new growth. It spreads fast and once established, McMahan warns, is very difficult to stop.
Another, taller groundcover is a form of Oregon grape called the long-leaf Oregon grape (Berberis nervosa). It grows several feet tall but can be sheared back every three to five years for an even stand. It forms spikes of bright yellow flowers in the spring followed by dark blue berries in summer. Birds love the fruit.
It is best to plant natives in the spring or fall after summer's heat has subsided. Additional irrigation may be needed until the groundcover becomes established.