Gray rabbit-brush is a low to mostly tall shrub covered with soft, gray, felt-like and dense hairs. The general shape of this shrub is open to rounded- or flat-topped. Plants range 50 cm to 2 meters tall and are abundantly branched. The numerous, erect stems are covered with persistent, dense hairs, giving the stem a grayish, felt-like appearance(thus giving the plant its name).
The leaves are linear with entire margins. Individual leaves are 2-7 cm long and about 0.5-3 mm wide. The leaves are tomentose to almost smooth, and are not twisted.
The yellow flower heads consist of cymose clusters of about 5 flowers each. Individual flower heads are discoid and narrow. The disk corollas are mostly 6.5-11 mm long. Gray rabbit-brush flowers in late summer to fall.
variety hololeuca: Taller plants from 40-150 cm high. Herbage of the stems and involucral bracts is of loose, gray to white tomentose hairs. The leaves are persistently tomentose and usually over 1 mm wide. Involucres mostly less than 10 mm long. Corolla lobes short, from 0.4-1.2 mm long. Found from southeastern Oregon south.
variety nana: Small plants from 10-30 cm high. Woody only at the base. Disk corollas 8-10 mm long. Involucres glabrous. Found at elevations of4000-6500 feet on dry rocky ridges and cliffs in the Blue Mts. and Wallowa Mts. of northeastern Oregon and southeastern Washington.
variety oreophila: Taller plants from 40-150 cm high. Herbage of the stems is tomentose but yellowish green. That of the involucral bracts is glabrous and sticky. The young leaves are tomentose but are soon glabrous. Leaves 0.5-1 mm wide with 1 nerve. The corolla lobes are less than 1 mm long. Often found in alkaline soils in Great Basin basins.
variety speciosa: Taller plants from 40-150 cm high. Herbage of the stems and involucral bracts is of loose, gray, white, or whitish-yellow tomentose hairs. The leaves are persistently tomentose and over 1 mm wide. Involucres mostly less than 10 mm long. Corolla lobes longer than variety hololeuca, from 1.2-2.0 mm long. From southern British Columbia south across eastern Washington and Oregon.
Gray rabbitbrush is a potential source for rubber. The flowers are grazed by wildlife and livestock in fall. The twigs are browsed by both pronghorn and mule deer, while the leaves are eaten by rabbits. This plant may be an aggressive weed on heavily grazed sites, and may also be found on disturbed fill slopes along roadways in the sage-grass steppe. Due to its silvery foliage, yellow flowers, and tendancy to draw butterflies and other pollinating insects, I believe it would also make a dandy shrub for the naturalized garden in areas east of the Cascade Mts. I can't attest for its resistance to wildfire, so plant it away from buildings and don't plant it under trees!
Gray rabbitbrush may be found in open dry place in the valleys, plains, and foothills, occasionally extending to moderate elevation in the mountains.
Gray rabbitbrush may be found from southern British Columbia south along the eastern edge of the Cascades to southern California, east to Saskatchewan and hence south to Texas and northern Mexico.