Mountain-ash, American
Sorbus americana
Rosaceae - Rose

Description

Leaves: Green and shiny on upper surface, paler underneath; fall color yellow, orange-red, or reddish purple; hairless; alternate; pinnately compound, large (6" to 12" in length); 7 to 19 leaflets, 1-1/2" to 4" in length, thin, lance-shaped, oblong-oval, tapering to a point, sharply toothed nearly to the base, deciduous; stalks often remain after leaflets have fallen; deciduous.

Twigs/buds: Twigs red-brown and hairy early on, become darker brown and hairless over time; stout, slow growing; with large pith, leaf scars, and lenticels. Buds dark red, sticky, scales nearly hairless, pointed; terminal buds dark brownish or gray brown, large (1/4" to 3/4" in length).

Flowers/fruit: Flowers perfect; white, 5-petaled with petals broadest towards tip; very small, clustered; clusters (cymes) flattened and dense; stalks hairless; occurring in mid-to-late spring, after leaves; somewhat similar to elderberry's flowers. Fruit a berrylike pome, bright shiny orange-red, almost ball-like, 1/4" to 1/2" in diameter, in flat-topped clusters, flesh thin, ripe in August, persisting into winter; seeds brown, 1/8" long, egg-shaped, 1-2 in number per cell.

Bark: Light gray to gray, thin; smooth with prominent horizontal lenticels when young; rough and scaly with age, often broken at base; inner bark fragrant.

Wood: Unimportant; heartwood pale brown, sapwood light-colored; wood weak, soft, light; close-grained, diffuse-porous.

General: A northeastern U.S. native similar to European mountain-ash (S. aucuparia). Naturally occurring in forest edges near moist sites like swamps, disturbed areas, on rocky outcrops, and on dry soils. A shrub or small tree, 10' to 30' in height, slow growing, and upright. Canopy is round-topped, open, somewhat sparse and narrow. Branches are spreading and slender. Relatively short lived. Shade intolerant.

Landscape Use: Less available than European mountain-ash (S. aucuparia), but could be planted in Utah. Buds are sticky and nearly hairless; and leaflets are longer. The flat-topped fruit clusters of mountain-ashes attract birds. Zones 2-6.

Characteristics

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