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Zones 3-11, 14-24
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Quercus douglasii

BLUE OAK
Fagaceae
Deciduous, Trees, Flowers

QUERCUS

The archetypal oak grows large and spreads wide, with muscular, near-horizontal lower branches that seem to defy gravity. But the group’s 500 species, all native to the Northern Hemisphere, also include upright, pyramidal, and shrubby oaks; in fact, “chaparral” comes from chaparra—Spanish for a dwarf evergreen shrub oak. Oak leaves can be deciduous or evergreen (the latter are called live oaks); lobed, toothed, or smooth edged; but they’re always arranged in an alternate pattern along stems. Some have terrific fall color. All oaks produce inconspicuous flowers followed by acorns, whose single nuts have cuplike caps covered with closely set scales. Some kinds of acorns are edible and sweet, while others are bitter and unpalatable.

Oaks come in two broad categories: white oaks have acorns that mature during the season in which they are produced, and often have leaves with rounded lobes; red and black oaks have acorns that take two seasons to mature, and often have leaves with pointed lobes. Each group can hybridize only within itself. 

Quercus douglasii

This deciduous tree is native to the dry foothills around California’s Central Valley and interior valleys of Southern California. Low branching, wide spreading; to 30–50 ft. tall and 40–70 ft. wide. Light gray bark is shallowly checked in small squares. Shallowly lobed, oval, bluish green leaves are 1 1/2–4 in. long, 3/4–2 in. wide. Attractive fall colors: pastel pink, orange, yellow. Egg-shaped, 3/4–1 1/4-in. acorns with sharply pointed tip and thin, flat cap. Good in dry, hot situations. Immune to sudden oak death.

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