Sorbus sitchensis
Common name: 
Sitka Mountain Ash
Pacific Mountain Ash
Western Mountain Ash
SOR-bus sit-KEN-sis
Native to (or naturalized in) Oregon: 
  • Deciduous shrub or small tree, usually multi-stemmed, to 20 ft (6 m) tall (only 1-2 m tall at higher elevations), rounded crown.  Trunk bark smooth or scaly, thin, light gray, inner bark fragrant.  Leaves alternate, pinnately compound, 10-20 cm long, usually 9-11 leaflets which are stalkless, each 3-6 cm long, elliptical or oblong, rounded or blunt at ends, margin serrate above the middle, dull to shiny blue-green above and pale below.  Flowers perfect (male and female parts) 6 mm wide, creamy-white petals, 4-5 styles, 20 stamen in 3 rows, 15-60 flowers per flat-topped clusters (corymbs), 7.5-10 cm across, "with a bit of an unpleasant (or unusual) odor" [Kruckenberg, 1996, p 115].  Fruit 9-12 mm diam., similar to a small apple, orange-red, bitter, acid, few seeds.  Fruit remain on the trees until late winter, making them available as winter forage for birds and small mammals.
  • Sun or light shade.  In its habitat it occurs in dry to moist, well-drained sandy loam or other soils.
  • Hardy to USDA Zone 5      Native range from southwest Alaska south along the Pacific Coast and through the Cascade Range to northern California and east to northern Idaho and northwestern Montana.  S. sitchensis (Sitka mountain-ash) hybridizes with S. scopulina ( Greene mountain-ash).
  • sitchensis: of Sitka, Alaska
Click image to enlarge
  • leaves and fruit cluster

    leaves and fruit cluster

  • leaves


  • developing fruit clusters

    developing fruit clusters

  • twig, bud and leaflets

    twig, bud and leaflets

  • leaves and fruit, fall

    leaves and fruit, fall

  • fruit and leaves, late summer

    fruit and leaves, late summer

  • plant habit, fall

    plant habit, fall

  • fruit and leaves, fall

    fruit and leaves, fall

  • leaves, fall

    leaves, fall