An evergreen shrub to 12 ft high, whose thorny branchlets are covered with a white bloom. Leaves alternate, ovate or broad-elliptic, 3⁄4 to 21⁄4 in. long, rounded at the apex, rounded to slightly heart-shaped at the base, dull greyish green above, paler beneath, almost glabrous; margins entire or slightly toothed; three-veined. Flowers white, borne in May in branched clusters 1 to 3 in. long.
Native of California, where it inhabits open places in the moist Redwood belt of the coastal range. 'It is a spreading bush which in bloom has a lovely grey effect: cream-white flowers in stiff, spiraea-like spikes with a pearly tinge, downy leaves or pale green young foliage, all against a background of grey-white stems' (Lester Rowntree in The New Flora and Sylva, Vol. 5, p. 155).