Berberis candidula (= B. hypoleuca) (western China)
Habit: Compact, domed small shrub, 0-4-0.8 m tall, 1.0-1.2 m wide; dense branches and foliage, shoots have many thorns, extended or bent to the ground, slow-growing.
Flowers: Single, yellow flowers, May; largely hidden by the dense foliage.
Fruits: Bluish black, hardly conspicuous.
Leaves: Evergreen, elliptical, shiny dark green varnish on top, strong bluish white underneath; occasionally with touches of bronze in winter; somewhat thorny at the edges.
Demands: Sun to semi-shade, usually frost hardy.
Soil: Fresh to moist, well drained, humic substrates, especially slow-growing on sand where it stays small; tolerates moderate droughts.
Note: Takes well to cutting.
Hardiness: Zone 6b