Sorbus sitchensis
Western mountain ash
(c) Peter Stevens, some rights reserved (CC BY) · licence
Family: Rosaceae · Type: Shrub / Tree · Native
Sorbus sitchensis (Western mountain ash) is a native California shrub / tree in the Rosaceae family, recognized by has varieties that may be more specific.
Western mountain ash is a native shrub found in montane and subalpine forest habitats at elevations typically between 1,000 to 2,500 meters. Flowering from May to July, this plant produces clusters of small white flowers with delicate ovate to diamond-shaped petals approximately 3 to 5 millimeters long. Growing 1 to 4 meters tall with reddish-brown stem buds that are glaucous and covered in evenly distributed hairs, it develops a distinctive branching structure. Its compound leaves have 7 to 13 leaflets, each 2 to 6 centimeters long and ovate to oblong in shape, with dull green surfaces and reddish-brown axillary hairs. The fruit is a bright red, glaucous berry 7 to 13 millimeters long, adding visual interest to the shrub in late summer.
Identification and appearance
Key characters: Geographically isolated according to sympatric analysis; has varieties that may be more specific
Habitat and range
California counties: El Dorado, Plumas, Tulare, Fresno, Tuolumne, Siskiyou, Modoc, Lassen, Alpine, Mono, Alameda, Mariposa, Madera
How to tell it apart
vs Sambucus: Mountain ash has narrow leaflets and pome fruits; elderberry has broader leaflets and true berries.; vs Heteromeles: Mountain ash has pinnate leaves with 9-15 leaflets; toyon has simple toothed leaves.; vs Nandina: Mountain ash has pinnate leaves once-divided; heavenly bamboo has leaves divided 2-3 times.; vs Schinus: Mountain ash has bright red-orange pomes; pepper tree has pink-red drupes and aromatic foliage.; vs Pyracantha: Mountain ash has deciduous pinnate leaves; firethorn has evergreen simple leaves and thorns.
Frequently asked questions
Is Sorbus sitchensis native to California?
Yes. Sorbus sitchensis is native to California (recorded as native).
Where in California does Sorbus sitchensis grow?
Sorbus sitchensis occurs in El Dorado, Plumas, Tulare, Fresno, Tuolumne, Siskiyou, Modoc, Lassen and other counties.
What plant family does Sorbus sitchensis belong to?
Sorbus sitchensis is in the Rosaceae family, genus Sorbus.
Related species
Other California species in the same genus, family, or bioregion.
- Sorbus sitchensis var. grayi — Dwarf or gray's mountain ash
- Sorbus sitchensis var. sitchensis — Sitka mountain ash
- Sorbus sp. — Mountain ash
- Sorbus aucuparia — European mountain ash
- Sorbus californica — California mountain ash
- Sorbus scopulina — Rocky mountain or cascade mountain ash
- Spiraea douglasii — Douglas spiraea
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.