Nearly all of Oregon is in the midst of a multi-year drought, with some areas experiencing the driest conditions in 1,400 years. Climate models predict that rising temperatures and declines in snowpack and glacial ice will cause drought conditions to become even more frequent and widespread across the state.
One way private landowners and managers can combat climate change and reduce the negative impacts of drought is to think about the plant communities in our own backyards. Landscaping with species native to your region conserves water (locally adapted plants require little irrigation) and reduces carbon pollution from exhaust, to say nothing of the chemical fertilizers and pesticides seeping into our watersheds. Lawns are the single largest irrigated ‘crop’ in America, requiring about 200 gallons of fresh, drinking-quality water per person per day to maintain.
Gardening with native, drought-tolerant plants protects our residential ecosystems, provides food and shelter for wildlife, filters rainwater, and reduces pollution– all while providing aesthetic value. Planting large, long-lived trees is especially effective at sequestering greenhouse gases.
The Benefits of Choosing Oregon Natives
Gardening with habitat restoration in mind is a form of environmental activism and can help reestablish ecological balance in the communities where we live and work. But how much of your yard needs to be native? Maybe some of your plants hold sentimental value, or you like to grow edibles like herbs and vegetables. Maybe you want some turf for kids to play on, or you just like to have a few specimen plants. Research shows that 70% native plant biomass is the ratio to aim for– prioritizing natives (especially keystone species that support important ecosystem services) promotes sustainable food webs in residential areas. So what should you plant?
Oregon has nine major ecoregions, many of which are connected by the Columbia River system. In the recent past, this system has experienced major changes wrought by development and the building of hydropower dams. Deciding what to plant in your own backyard will depend on your ecoregion and site conditions, including soil (what kind of habitat was this land formerly?), light, and moisture levels. Since most of Oregon is deep in a historic drought, let’s talk about the best drought-tolerant plants.
Canopy Trees
1) Oregon white oak (Quercus garryana)
Oregon’s Prairie-Oak ecosystems are among the most iconic– and the most imperiled in North America. The majestic Oregon white oak or ‘Garry oak’ is a keystone species of the Pacific Northwest and the host plant to at least 436 caterpillar species. Historically, its range spans from southwestern British Columbia (including Vancouver) down through California. It is particularly suited to forest edges with high exposure and drought conditions where it can outcompete maples and Douglas firs (making it an excellent choice for residential areas).
Q. garryana has deep tap roots and likes a lot of sun– a good choice for a warmer, drier Oregon. Its bark and rounded, richly lobed leaves are tough and leathery, making it fire-resistant. The oldest known specimen is at least 400 years old, and almost 100 ft tall. Young trees grow at a rate of about 1 – 2 ft per year, and mature trees top out at a minimum of 60 ft (that’s a lot of biomass!). Oaks are valued for their shade, lumber, and the fact that they support more life forms than any other tree in North America. If you can only plant one thing, make it an oak!
2) Ponderosa pine (Pinus ponderosa)
The ponderosa or ‘yellow pine’ is another classically recognizable giant of the Pacific Northwest. Its historic range stretches from Canada down to Mexico. In Oregon, studies of pollen counts in deep cores from Willamette Valley bogs are able to establish its presence as far back as 10,000 years. The ponderosa is also a keystone species, hosting at least 200 moths and butterflies.
The bark of young trees is dark reddish-brown to black but brightens into a rich cinnamon color with age. The needles are five to ten inches long, bundled in clusters of three. The seedlings grow down before they grow up, developing a deep taproot that helps them endure heat and drought once established. Additionally, conifers have special physiological mechanisms that help them transport water internally during dry, cold winters. At maturity, the bark can be thicker than four inches, making it resistant to wildfire as well. Adult trees are long-lived and can grow in excess of 150 feet tall.
Ponderosas are one of the only plants that can survive on Zone 3 upland terraces. Birds and small mammals eat the seeds and needles, and trees are frequently chosen as nesting sites– notably, P. ponderosa is a favorite of the federally endangered northern spotted owl. This tree is best for large spaces.
3) American aspen (Populus tremuloides)
The American or quaking aspen is a popular choice as an ornamental tree, with many cultivars available. Famous for its striking white bark and rounded, green-and-silver leaves, P. tremuloides is the most widely distributed tree in North America– on the West Coast it ranges from Alaska down to northern Mexico. In the fall the leaves are golden-yellow to orange. Quaking aspens sucker to form groves, so plan accordingly if planting this species in your yard. These trees are resilient during times of water stress and are fire-resistant. They prefer full sun to partial shade.
Research has shown that wild-growing aspens increase their drought tolerance by growing stronger and denser branches and tissues, and studies of nursery-grown aspens found that seedlings might be conditioned to better withstand drought; trees subject to low irrigation levels in the experiment actually grew taller and had higher rates of photosynthesis. Nearly 250 species of caterpillars use quaking aspens in Oregon, and its bark, buds, and foliage all provide food for wildlife. In urban environments, trees may be more susceptible to pests or diseases.
4) Douglas maple (Acer glabrum var. douglasii)
The Douglas maple (the subspecies native to Oregon) is a handsome, upright tree with a beautiful natural shape (avoid pruning to let it develop its own character). Easy to grow, this maple adapts well to drought, poor soils, and high winds. In the fall, the leaves turn bright yellow with a subtle red tinge, and its ‘helicopter’ seeds have an attractive reddish color in the summer. The Douglas maple is a smaller tree (30 ft) that prefers full sun to partial shade. It is a host plant for 238 species of caterpillar, making it highly valuable to wildlife.
5) Pacific madrone (Arbutus menziesii)
The madrone is a treasured symbol of the Northwest and is highly recognizable with its red peeling bark, white bell-shaped flowers, and red-orange berries. Possibly one of the most drought-tolerant trees in the region, its roots can penetrate up to 12 feet of bedrock to seek out groundwater. Madrones are notoriously hard to transplant, so it’s best to choose the smallest seedling you can find, and plant multiple trees to improve chances of success– young trees will grow between one and three feet per year.
Seedlings do best when planted in at least partial shade, but older trees will require top light to survive. Be careful not to cramp the roots when planting and do not overwater (once a tree is established, it may need no watering at all). Some nurseries might have seedlings labeled with the directional orientation the plant is used to, which could increase survival rates. This tree is best for larger yards.
Understory Trees & Shrubs
1) Chokecherry (Prunus virginiana)
The chokecherry can be grown as a small to medium-sized tree (topping out at about 40 ft) or as a large shrub. In the spring it drips clusters of fragrant flowers that have special value for native bees and other pollinators. Leaves turn a striking reddish-purple in fall, and deep purple berries ripen in September – October. The berries are eaten by birds and other animals and are also edible to humans as jams, jellies, or wine (but may be bitter-tasting without added sugar). This plant is extremely drought-tolerant and fire-resistant. It Likes full sun and may produce some suckers.
2) Oregon grape holly (Berberis aquifolium)
Also called tall Oregon grape or holly-leaved barberry, this 5 – 6 ft shrub is semi-evergreen– its leaves turn burgundy in fall and hang on through winter, providing a pop of color in gray winter landscapes. It prefers partial sun. The flowers (Oregon’s state flower) are a striking lemon yellow against the burgundy in spring, and provide nectar and pollen for many pollinators, including hummingbirds. Flowers are followed by blue-black berries that feed a variety of wildlife– birds, foxes, and raccoons are especially fond of them. Like chokecherry fruits, the berries are edible to humans but tart. Consider also the smaller, more compact creeping holly (Mahonia repens).
3) Greenleaf manzanita (Arctostaphylos patula)
Greenleaf manzanita or buckbrush is an oval-shaped evergreen shrub that grows to 7 ft tall, and prefers full sun and well-drained soil– it can survive long periods of drought. Often chosen for formal landscapes due to its ornamental properties, this native shrub also provides habitat and food for wildlife with its foliage, fruits, and seeds. Its leaves are a bright glossy green, and the bark is a polished reddish-brown that provides remarkable winter interest and peels in tight curls with age.
The flowers are nodding clusters of dainty pink bells, followed by small black-brown fruits shaped like miniature apples (manzanita is Spanish for ‘small apple’). Native to the mountain chaparral, lava flats, and buttes of the American West and Southwest, this species makes a fine addition to rock gardens, especially paired with smaller shrubs and boulders.
4) Desert sweet (Chamaebatiaria millefolium)
Desert sweet or fern bush is a pearl of rocky mountain slopes in the West and another Oregon native. Once established, this plant uses very little water and is hardy during long droughts. Foliate buds (visible next year’s growth) in winter make desert sweet a semi-evergreen focal point in any garden; it pairs especially well with ornamental grasses.
From June to August, it is teeming with clusters of small white flowers that are of special value to native bees and other pollinators. Its lacy foliage is aromatic and may have medicinal properties. A low-maintenance and attractive choice for drier garden areas.
5) Gray rabbitbrush (Ericameria nauseosa)
Gray rabbitbrush or Chamisa is a fall bloomer, with showy yellow flowers and a pungent odor sometimes described as ‘pineapple-like’ or rubbery. Its native range extends from British Columbia down through northern Mexico, and it is often found in the wild with sagebrush. As a landscape plant, it is extremely low-maintenance and will thrive with little to no interventions or supplemental watering. It is salt- and drought-tolerant.
Gray rabbitbrush forms a mound 2 – 5 ft tall, sometimes up to 7 ft. Its silvery-green stems are long and slender, often woolly, and when broken, weep a milky latex that contains a high-grade rubber compound. This species is being evaluated for potential use in the production of rubber, resin, antimalarial drugs, insect repellents, and more.
6) Golden currant (Ribes aureum)
A common plant found east of the Cascades in Washington and Oregon, golden currant is a favorite of hummingbirds, butterflies, and other beneficial insects. Its cheerful, tubular yellow flowers bloom through spring, and it produces edible berries that ripen in late summer and support a variety of birds and other wildlife. Its fall foliage is orange to red. Golden currant prefers full sun to partial shade and does well in either moist or dry sites. It can grow to be 6 – 8 ft tall, with a similar spread. This plant is lovely mixed in with evergreens as a privacy screen, or in pollinator gardens!
7) Snowberry (Symphoricarpos albus)
Snowberry is an easy-to-grow, thicket-forming deciduous shrub that does well in full sun to partial shade, and in a variety of soils. It can withstand long droughts, but also thrives in streamside habitats or on slopes where it provides erosion control– it is often found growing wild this way on either side of the Cascades.
The pinky-white tubular flowers are favorites of Anna’s and rufous hummingbirds. Its round, waxy white berries are beautiful in winter (especially paired with the red rosehips of Oregon’s native rose) and are eaten by birds (notably waxwings, grosbeaks, and towhees). Snowberry is the larval host plant of the Vashti sphinx moth and of the snowberry clearwing moth in other parts of its range.
8) Oceanspray (Holodiscus discolor)
Oceanspray or ‘cream bush’ is recognizable for its delicate, frothy sprays of white flowers, similar to lilac or hawthorn blooms. Often seen on roadsides between the Willamette Valley and the coast (and in disturbed sites in nearly every county in Oregon), this species also makes a great choice for butterfly or pollinator gardens.
Oceanspray grows best in partial shade, but also tolerates full sun and full shade, and flourishes in any garden soil. It requires little to no maintenance or watering. The plant is favored by indigenous Americans for its strong, flexible wood as a construction material, and to make arrow shafts. Its fall foliage is yellow to red. The plant grows to a height of 10 – 15 ft, but can take heavy pruning each season.
Forbs & Grasses
1) Roemer’s fescue (Festuca roemeri var. roemeri)
Roemer’s fescue is a slow-spreading perennial bunchgrass with blueish-green leaves and a fine texture. Its seed heads are dainty and upright. An Oregon native, this short, cool season grass has an extensive root system that helps it endure long periods of drought. Roemer’s fescue prefers full sun, but will tolerate partial shade. It requires little to no irrigation but needs good drainage and cannot withstand flooding or saturated roots.
2) Silky mountain rice (Eriocoma hymenoides)
Silky mountain rice or Indian ricegrass is an edible native bunchgrass that is often chosen for dry floral arrangements. It forms clumps 4 – 24 inches high and 8 – 12 inches wide. One of the most drought-tolerant grasses of the region, this species has deep, fibrous roots and is great for dry, rocky gardens and erosion control. Its seed heads are gauzelike and form graceful arches. Silky mountain rice is an important food source for both wildlife and domestic livestock.
3) Prairie junegrass (Koeleria macrantha)
Prairie junegrass is another clump-forming, native cool-season grass that grows 6 – 24 inches tall. The leaves are blueish-green to purple, with silvery flowers and seed heads. It requires very little water (as little as 14 inches of precipitation per year) and has high drought tolerance due to its fibrous root system.
A useful plant for restoration areas, revegetation of disturbed sites, and erosion control, this species also provides ornamental interest in a home landscape interspersed between wildflowers or smaller shrubs. It may also be used as a low-input turf grass– a European cultivar named ‘Barkoel’ has been specially developed for use as turf.
4) Blanket flower (Gaillardia aristata)
Blanket flower is a sun-loving native perennial that makes an excellent cut flower and may be easily grown from seed (though it may not bloom in its first season). It prefers well-drained or sandy soil, but grows well in a variety of conditions and is quite resistant to drought. The plant can reach heights of 1 – 3 ft. Its flowers are usually purple to red around the central dome and yellow at the tips.
There are many blanket flower varieties available at nurseries. A member of the sunflower family, this species is highly attractive to bees and butterflies, but is also pollinated by bats! It is a larval host plant for the Schinia masoni flower moth, which has evolved to camouflage itself (yellow head, burgundy wings) with the petals.
5) Pacific bleeding heart (Dicentra formosa)
An exquisite ornamental flower, the Pacific bleeding heart is a recipient of the Royal Horticultural Society’s Award of Garden Merit. This hardy, shade-loving perennial is also a common Oregon native, found in dappled sun in hardwood forests all over the state. It prefers rich, fertile soil and may seem delicate, but is able to survive some droughts and harsh winters due to its extensive rhizomatous root system. Pacific bleeding heart is also highly resistant to fire.
This species dies back after blooming, so is best mixed with summer-peaking plants in a garden setting. Its magenta, six-petaled flowers are highly attractive to hummingbirds, but all parts of the plant are poisonous to humans and pets if ingested.
6) Western columbine (Aquilegia formosa)
Western or crimson columbine is a summer-blooming member of the buttercup family and is extremely adaptable. This plant can grow in a wide variety of sites and conditions but is likely to be happiest in partial shade and rich, well-drained soil. Easy to grow but short-lived, this perennial readily self-seeds and hybridizes with other columbines, making it a fun plant to experiment with in your garden. Its bright and ethereal trumpet-shaped flowers grow between 1 – 3 ft tall, and are reddish-orange and yellow with spurs. Western columbine is a magnet for hummingbirds.
7) Oregon sunshine (Eriophyllum lanatum)
Oregon sunshine or ‘woolly sunflower’ is a pollinator powerhouse and an easy-to-grow perennial with cheerful, disc-shaped yellow flowers. It may bloom from May – July or June – September. This plant is a larval host for the painted lady butterfly and numerous other species of Lepidoptera. It grows to 2 ft tall, but can be cut back if it becomes too leggy.
Oregon sunshine’s silvery-green, ‘woolly’ stems are actually an important adaptation with regard to drought tolerance; the hairs or trichomes conserve water by reflecting heat and trapping air on the leaf’s surface. The plant requires little to no irrigation (may suffer from overwatering) and is an excellent low-maintenance plant for a home landscape.
8) Cascade penstemon (Penstemon serrulatus)
While most penstemons or ‘beardtongues’ are drought-tolerant, cascade or coast penstemon is an Oregon native and is thought to be one of the most adaptable species around. This shrubby, semi-evergreen beardtongue does best in moist sun and is a good selection for perennial borders and containers.
Its bright amethyst, trumpet-shaped flowers are irresistible to hummingbirds and other pollinators. Considered to be the best beardtongue for gardens west of the Cascades, P. serrulatus is also a popular ornamental outside of its native range. Many colors and varieties of penstemon are available at nurseries.
9) Orange globe mallow (Sphaeralcea munroana)
Orange globe or Munro’s globe mallow is a showy cool-season perennial found in mixed desert shrub and sagebrush habitats in Oregon. Its blooms are salmon-pink saucers that peak in late summer and are visited by a variety of bees and other pollinators. Orange globe stems are upright and covered with white, star-shaped hairs. The plant is well adapted to disturbed sites and open, dry areas and is perfect for rock gardens and water-wise borders or containers. Orange globe is propagated by seed.
Groundcovers
1) Creeping phlox (Phlox diffusa)
Creeping or spreading phlox is a mat-forming perennial wildflower native to open woodlands or rocky mountain slopes in Oregon. Its foliage is needle-like in appearance, but soft, and yellow-green. Its tubular, 5-petaled flowers are small but profuse and can be white, pink, purple, or light blue. Creeping phlox blooms from late spring to summer. This plant is attractive to bees and butterflies and is a good choice for rock gardens or driveway beds– it looks charming spilling over border walls!
2) Pink pussytoes (Antennaria rosea)
Pink or rosy pussytoes are low-growing perennials that form evergreen mats and can even take some light foot traffic. Its blooms are cream to rose, and resemble a cat’s paw– the most colorful species of pussytoes are often a delight to children. It is a host plant to the American lady butterfly and a popular choice for butterfly and pollinator gardens. It is also a good selection for rock gardens where its soft, glossy foliage will cascade over stones. This plant requires very little water but needs well-draining soil. It’s native to the West and Great Plains, up through Alaska.
3) Sulfur-flower buckwheat (Eriogonum umbellatum)
Sulfur flower or slender buckwheat is a low-growing native perennial of sagebrush communities, dry, rocky slopes, and sunny exposures on ridges. Its flowers are showy yellow-orange (sometimes rusty) clusters of tiny blooms. A keystone species, this plant is critical to ecosystem health and an important pollinator plant. Its seeds are eaten by a variety of birds and wildlife. The rare cuckoo bee genus Stelis has been documented on this plant by Oregon Bee Atlas participants.
The sulfur flower is a great plant for foundation plantings around mountain homes, rock gardens, or for erosion control on dry, sunny slopes. It is highly resistant to drought, heat, and wind. The plant is widely used for medicinal purposes by indigenous Americans to treat a number of conditions.
4) Kinnikinnick (Arctostaphylos uva-ursi)
Kinnikinnick or bearberry is a low-growing, woody evergreen shrub that loves the sun and performs well in poor soils. It may grow well on bare limestone rock and is salt- and drought-tolerant. Its leaves are a lustrous green and spring blooms are pinkish-white and bell-shaped; berries are bright red in fall. It can grow 4 – 6 ft tall and spread 3 – 15 ft wide.
The plant is a great focal point for a rock garden and may help stabilize the soil. Bearberry looks very attractive spilling over border walls. It provides food for a variety of wildlife, including bears (hence the name ‘bearberry’), grouse, foxes, and frugivorous birds. The plant is used by indigenous peoples in many traditions, both medicinal and religious. Kinnikinnick is notoriously difficult to transplant, but many cultivars are available.
A Note on Vegetable Gardens
One way to make sure your edibles survive the dry season and produce optimal yields is to plant crops that are already suited to drought conditions on a cellular level. Tepary beans for example are an ancient superfood that has been grown and harvested in the American Southwest for millennia– they have adapted to grow in desert conditions. Black-eyed peas and okra are also good choices, as they need long warm summers to reach maturity. Likewise, plants that develop deep root systems quickly and can access deep, moist soils will fare better than those with shallow roots after the surface has gone dry; these include tomatoes, squash, melons, and specially bred cultivars like ‘Dark Star’ zucchini.
Ensuring that crops get adequate watering early on in the growing season helps to establish deep, healthy root systems. Watering shallowly and too frequently can encourage roots to grow laterally in surface soils, making them vulnerable to water stress during drought conditions. Hand watering is preferable to sprinklers, and drip irrigation systems are a handy option that requires a bit of investment upfront but conserves a lot of water in the long run. Keep an eye on your plants– over-watering can cause suffocation, and too little moisture can push more sensitive species past the brink of recovery in just a day or two.
Turf Grass
Lawns are a staple of American yards and are deeply tied into our ideas about homeowner status and community. Perfect turf has historically been an indicator of wealth and success in the United States, but those views are changing. ‘Drought shaming’ one’s neighbors is an increasingly common phenomenon in the West, and lawn alternatives and ‘bee lawns’ are growing in popularity. Turf grass is still advantageous in some situations, however; a lawn can provide a barrier for fire, reduce erosion and ground temperatures, and slow down stormwater runoff– it can also withstand a lot of traffic (like children playing).
Choosing the right grass for your Oregon yard can be tricky. Counterintuitively, warm-season grasses with high drought tolerance– like buffalograss or Bermuda– are difficult to establish because of cool conditions during the growing season. Adaptable cool-season grasses like tall fescue are the best, most drought-tolerant option, and may be combined with more traditionally planted species (Kentucky bluegrass, fine fescues, ryegrass, etc.).
