Sorbus sitchensis

Common Names

Sitka Mountain Ash, Pacific Mountain Ash, Western Mountain Ash

Summary

Sitka Mountain-ash is a native deciduous shrub or small tree of the Rosaceae, occurring from Alaska and Yukon south to California and east to Idaho and Montana, typically forming a multi-stem habit in open conifer forests, streambanks, meadow edges, and rockslides. Leaves are pinnately compound with 7–11 blue-green leaflets; white flowers appear in flat-topped clusters, and pinkish red to red pomes follow, persisting into late fall.

Hardiness zones 4–8; grows in sun to light shade with moist, well-drained soils and tolerates poorer soils, often used for streambank rehabilitation and as an ornamental plant that provides wildlife forage. Propagation is by seed, with germination requiring stratification of 60+ days at 32–41°F; transplant after two years and plant with about 3 feet on-center spacing; fruits are edible raw or cooked but of poor quality, sweeter after frost.

Lifecycle

Perennial

Height

3-12 feet

Spread

3 feet

Hardiness Zones

Zones 4-8

Sunlight Requirements

Full Sun, Partial Sun, Partial Shade, Full Shade

Soil Type

Moist, well-drained soil

Soil Drainage

Moist, well-drained soils

Soil pH

6-7.2

Bloom Color

White

Bloom Time

Summer

Foliage Color

Blue-green

Fall Foliage Color

Yellow, orange and red

Leaf Lifecycle

Deciduous

Growth Rate

Slow

Seasons of Interest

Spring, Summer, Fall, Winter

Propagation Methods

Seeds, Cuttings (difficult), Layering, Division

Attracts Wildlife

Attracts birds, attracts other pollinators