Quercus berberidifolia aka California Scrub Oak

Quercus berberidifolia is an evergreen oak in the beech family, Fagaceae. Its common names include California scrub oak and inland scrub oak. It grows wild in California and Baja California, Mexico. Its range includes California’s Coast Range and Sierra Nevada. It also occurs in the mountains of southern California. The name berberidifolia refers to leaves that resemble barberry leaves.

This oak forms a dense shrub, sometimes becoming a small tree. Plants reach about 3–15 feet (0.9–4.5 metres) tall. Many stems form a thick clump rather than one clear trunk. Closely packed twigs and leaves can make a hard-to-cross barrier. This dense form gives it value where a barrier is useful. Sources describe gray bark with either a smooth or scaly surface. Smooth bark may show many small pores, called lenticels. Slender twigs range from gray or yellowish to reddish brown. Round to pointed buds gather in clusters along the twigs.

The stiff, leathery leaves stay on the plant year-round. They grow one at a time along the stems. Their shapes range from oval to broader near the tip. Leaf bases may look rounded, flat, or slightly heart-shaped. Edges bear uneven teeth, which may end in sharp points. The green upper face can be shiny, flat, or wavy. The lower face is gray-green and may have fine hairs. Short leaf stalks hold the blades close to the stems.

Each plant bears both male and female flowers. Yellow-green male flowers hang in catkins as new leaves appear. Tiny female flower spikes sit where leaves meet the stems. The brown acorns have an egg-like shape. They grow alone or in pairs, with no stalk beneath the cup. A deep, warty cup covers roughly one-third to half the nut. Acorns mature within one season, from late summer into early fall. This species can cross with several other oaks. These include Oregon white oak and valley oak.

Grow this oak in sun or light shade. It needs soil that drains well and withstands drought. Oregon State places its cold hardiness mainly in USDA zone 8. Its listing also suggests some tolerance of zone 7 conditions.