Plants that thrive in Seattle, WA
Seattle has wet winters and a real summer drought, so the plants that work here tolerate both saturated winter soil and six to ten dry weeks in summer. Evergreen huckleberry, Oregon grape, red-flowering currant, sword fern, oceanspray, sedum, and Pacific Coast iris are the dependable core. The two site problems specific to Puget Sound are glacial hardpan that holds winter water above it, and shade so deep under conifers that most flowering plants sold locally will not bloom in it.
Seattle growing conditions at a glance
- USDA hardiness zone
- 8b
- Region
- the Puget Sound lowlands
- Rainfall
- about 38 inches a year, almost none of it from July to mid September
- Soil
- glacial till, often with a dense compacted hardpan layer under a thin topsoil
- Hardest condition to design around
- the dry summer nobody expects. Seattle's reputation is rain, but July and August are genuinely dry, and glacial hardpan means winter beds stay waterlogged
Shrubs and small trees
Northwest natives that handle a saturated winter and then go weeks without rain in August.
Evergreen Huckleberry
Vaccinium ovatum
- Sun
- Part shade to full shade
- Water
- Low to moderate
- Mature size
- 3 to 6 ft in shade, taller in sun
Caveat: One of the best evergreen shrubs for real conifer shade, with edible berries. It is slow, and it needs acidic soil with organic matter, so it struggles in scraped construction subsoil without amendment.
Tall Oregon Grape
Berberis aquifolium
- Sun
- Part shade to full sun
- Water
- Low
- Mature size
- 5 to 8 ft
Caveat: Evergreen, yellow spring flowers, blue fruit, and it suckers into a colony. Leaves are spiny like holly, and in full sun with dry soil the foliage bronzes and looks stressed.
Red-flowering Currant
Ribes sanguineum
- Sun
- Part shade to full sun
- Water
- Low
- Mature size
- 6 to 10 ft
Caveat: The earliest hummingbird plant in the Northwest, flowering in March, and it goes summer dormant, dropping leaves in a dry August. That is normal, not a dying plant, but plan for it to look bare in late summer.
Oceanspray
Holodiscus discolor
- Sun
- Full sun to part shade
- Water
- Very low
- Mature size
- 8 to 15 ft
Caveat: Extremely drought tolerant once established and it holds tan spent flower clusters into winter, which some people find untidy. It is an informal, arching shrub, not a hedge plant.
Ferns and shade groundcovers
The layer that replaces English ivy under Douglas firs and big-leaf maples.
Western Sword Fern
Polystichum munitum
- Sun
- Part to full shade
- Water
- Low once established
- Mature size
- 3 to 4 ft
Caveat: The defining Northwest shade plant, and it needs a couple of years of summer water to establish before it can handle dry shade. Cut last year's fronds off in late winter for a clean flush.
Salal
Gaultheria shallon
- Sun
- Part to full shade
- Water
- Low
- Mature size
- 2 to 4 ft, spreading
Caveat: Tough evergreen native that spreads by rhizome and is famously slow to establish, often sitting still for two years before taking off. It also resents being transplanted from the wild, so buy nursery stock.
Redwood Sorrel
Oxalis oregana
- Sun
- Full shade
- Water
- Moderate
- Mature size
- 6 to 8 in, spreading
Caveat: Excellent in deep shade where nothing else covers, and it wilts dramatically in any direct sun, recovering at night. It goes semi-dormant in a dry summer without water.
Sun perennials and grasses
For the strip of Seattle yard that actually gets sun, and for winter drainage problems.
Pacific Coast Iris
Iris douglasiana hybrids
- Sun
- Part shade to full sun
- Water
- Low, dry in summer
- Mature size
- 12 to 18 in
Caveat: Evergreen, spring flowering, and it must be kept dry in summer or the rhizomes rot. Divide it in fall, not spring, or it sulks for a season.
Autumn Stonecrop
Hylotelephium 'Autumn Joy'
- Sun
- Full sun
- Water
- Very low
- Mature size
- 18 to 24 in
Caveat: Reliable late-season color and it flops in a wet Seattle spring if the soil is rich. Pinch it back by half in early June to keep it upright, and give it sharp drainage.
Tufted Hair Grass
Deschampsia cespitosa
- Sun
- Full sun to part shade
- Water
- Moderate, tolerates wet
- Mature size
- 2 to 3 ft in bloom
Caveat: A Northwest native that tolerates a rain garden or a bed that stays wet all winter. It is semi-evergreen and looks scruffy by February, so comb it out in late winter.
What should you not plant in Seattle?
Skip English ivy, Himalayan blackberry, butterfly bush (Buddleja davidii), and yellow archangel, all listed noxious or invasive in Washington. Butterfly bush in particular is still sold in some places and is a regulated Class B noxious weed in parts of the state; sterile cultivars are the only defensible version.
What are the watering rules in Seattle?
Seattle Public Utilities runs voluntary summer water-savings programs rather than routine mandatory restrictions, and Seattle's Green Factor score applies to many new commercial and multifamily projects, rewarding native and drought-tolerant planting. Saving Water Partnership rebates and plant lists are the regional reference.
Water rules and rebate programs change. Confirm the current stage and schedule with your local water provider before relying on it.
Questions
Do plants in Seattle need summer watering?
Yes. Despite the region's reputation, Seattle gets almost no rain from July into mid September, so new plantings need regular summer water for their first two to three years. Established Northwest natives such as oceanspray, salal, and sword fern can then go through a dry summer on their own.
What plants grow in deep shade under Douglas firs?
Evergreen huckleberry, sword fern, salal, redwood sorrel, and Oregon grape all grow in the dry, root-filled shade under conifers. Expect foliage rather than flowers there: most flowering shrubs sold locally need more light than a mature conifer canopy allows.
What is glacial hardpan and why does it matter in Seattle yards?
Much of the Puget Sound lowland sits on compacted glacial till, a dense layer beneath a thin topsoil that water cannot easily pass through. Winter rain perches above it, so beds stay saturated for weeks even on a slope. The fix is usually raising planting areas and choosing wet-tolerant plants rather than trying to dig through the layer.
What should I plant instead of English ivy in Seattle?
Salal, sword fern, redwood sorrel, and low Oregon grape are the native replacements for English ivy in Northwest shade. Ivy is a listed noxious weed in Washington and pulling it out is usually the highest-value first step in an older Seattle landscape.
Want a plant list matched to your specific yard rather than Seattle in general? See how Dream Landscaper designs against your actual conditions, or skip ahead and get your free concept.
Other city plant guides
10 plants covered. Mature sizes and water needs are typical ranges for the Seattle, Washington area and vary with microclimate, soil depth, and care. Nothing here is a substitute for a soil test or local extension advice.