Empetrum nigrum

Low, branching subshrub with glabrous linear leaves and purplish flowers in spring followed by black, berry-like drupes.  6 - 12" tall and spreading along the ground over time.  Grow in part shade in moist, acidic, well-drained soil.  Hardy to -30 degrees F  Found in coastal cliffs from Northern California north to Alaska and in arctic regions throughout the Northern hemisphere.  Ericaceae

Empetrum means "on rocks" and refers to its native habitat.