Berberis repens

Berberis repens commonly known as creeping mahonia, creeping grape holly, or creeping barberry, is a species of Berberis native to most of the western United States and two western provinces of Canada. It is low growing shrub that spreads by underground stems. As a species it is well adapted to fire and is a very common understory plant in western forests. An evergreen species, it provides food to deer and elk in winter and can make up a significant part of their diet. The berries are eaten by birds and small mammals, aiding it in spreading to recently disturbed areas. It has found use as a xeric ornamental plant and has escaped from cultivation in areas beyond its native range.