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Sorbus sitchensis

Sorbus sitchensis M. Roem.

Western Mountain Ash, Sitka Mountain-ash

Rosaceae (Rose Family)


USDA Symbol: SOSI2

USDA Native Status: L48 (N), AK (N), CAN (N)

A 3-12 ft. shrub with many erect to spreading stems from a common base. Foliage is pinnately compound with 7-9 toothed leaflets. Flowers are small and white in dense, flat-topped clusters. They are followed by huge clusters of big, reddish-orange, persistent berries. Fall foliage is yellow to bronzy-red.

The Sitka Mountain Ash is a member of the family Rosaceae which includes about 2000 species of trees, shrubs, and herbs worldwide; approximately 77 native and 9 naturalized tree species and many species of shrubs and herbs in North America; including service-berries (Amelanchier), hawthorns (Crataegus), apples (Malus), plums and cherries (Prunus), and mountain-ashes (Sorbus).


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Plant Characteristics

Duration: Perennial
Habit: Shrub
Leaf Retention: Deciduous
Fruit Type: Pome
Size Notes: Up to about 12 feet tall.
Autumn Foliage: yes
Fruit: Red

Bloom Information

Bloom Color: White , Pink
Bloom Time: Mar , Apr , May , Jun , Jul
Bloom Notes: White, rarely pinkish.


USA: AK , CA , ID , MT , OR , WA
Canada: BC
Native Distribution: AK & Yukon, s. through mts. to n. CA, e. to e. B.C., n. ID & n.w. MT
Native Habitat: Wooded or open, upper montane to subalpine slopes

Growing Conditions

Light Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist
Soil Description: Moist to drier, well-drained soil.


Use Wildlife: Grouse, cedar waxwings & grosbeaks consume the berries.
Attracts: Birds


Description: Usually propagated by seed sown fresh in fall or stored and stratified.
Seed Treatment: Cold stratify at 32 degrees for 2-4 months.
Commercially Avail: yes

Find Seed or Plants

Find seed sources for this species at the Native Seed Network.

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Native Seed Network - Corvallis, OR


Bibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.

Search More Titles in Bibliography

Web Reference

Webref 30 - Calflora (2018) Calflora
Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter

Additional resources

USDA: Find Sorbus sitchensis in USDA Plants
FNA: Find Sorbus sitchensis in the Flora of North America (if available)
Google: Search Google for Sorbus sitchensis


Record Modified: 2022-10-21
Research By: TWC Staff

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