Dwarf Mahonia (Berberis aquifolium var. repens) is a native plant, growing in the mountains and foothills of the northern part of California. It enjoys dry shade below 700 ft. It can be found as far north as SE Alaska and eastern Alberta to central New Mexico. Outside its native range it qualifies as invasive. Dense yellow clusters of flowers give way to round dusty dark purple-blue berries, hence the common name Oregon Grape. The edible berries can be used to make wine and purple dye. Some sources describe it as toxic, however. The inner stem gives a yellow dye.
Dwarf Mahonia is very drought tolerant, and very easy to grow, but it looks better with a little bit of summer water.