Western Mountain-Ash

Common Name(s): Western Mountain-Ash, Greene's Mountain-Ash, Mountain-Ash.

Scientific Name: Sorbus scopulina. Scopulina means "of the rocks or cliffs".

Plant Symbol: SOSC, sosc.

General Info: A several-stemmed deciduous shrub, 1 to 5 m (3-15 ft) tall.

Native/ Non-native: Native.

Ecology: Widespread and common at low to subalpine levels in moist forests, openings and clearings. Generally absent from warmer, arid areas.

Range: Western mountain-ash is native to broad areas in the southern half of Alaska, and broad areas of the Yukon, Northwest Territories, British Columbia, Alberta, Saskatchewan, Montana, Idaho, Washington, and scattered areas in Oregon, California, Wyoming, North Dakota, South Dakota, Utah, Colorado, Nevada, and New Mexico.

Flowers: White and small, up to 200 in flat-topped to rounded clusters. May - early July.

Fruits: Orange to scarlet glossy berry-like pomes, which persist into winter.

Leaves: Alternate, divided into 9-13 oblong yellow-green leaflets with sharp pointed tips. Most of the length of a leaflet is sharply toothed.

Notes:

Winter buds and early growth are white-hairy and sticky to the touch (as contrasted to the the Sitka Mountain-Ash). (See photo at right.)
Many birds eat the berries, and moose and deer browse on the twigs.
The mountain-ash are not ash trees, but leaflets are thought to resemble the ash.

Resources/ Links:

http://www.fs.fed.us/global/iitf/pdf/shrubs/Sorbus%20scopulina.pdf

Field Guide to Forest Plants of Northern Idaho (Patterson, Neiman, Tonn), 1985 USDA – Forest Service

Plants of Southern Interior British Colombia and the Inland Northwest (Parish, Coupe, Lloyd), 1996

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Above: The berry-like pomes turning orange in late summer... Sharply pointed and toothed leaves...

Below: Young reddish bud, sticky to the touch, leafing out in early spring. (Note the white hairs as well...)

Below: Multi-stemmed at ground level.

Photos by Wendy Aeschliman