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Quercus douglasii Hook. & Arn.
USDA Symbol: QUDO
USDA Native Status: L48 (N)
Tree with short, leaning trunk; short, stout branches; broad, rounded crown; and brittle, hairy twigs; sometimes shrubby. Blue oak is a deciduous oak, usually growing to 30 ft., but sometimes reaching 50 ft. The crown is rounded. Bluish-green leaves are shallowly lobed, without bristles. Bark is light-colored and checked into thin scales.
Recognized from a distance by the bluish foliage, this handsome California oak was named for its discoverer, David Douglas (1798-1834), the Scottish botanical explorer. It is used principally for fuel. The acorns, often abundant, are eaten by livestock as well as by wildlife.
Plant CharacteristicsDuration: Perennial Habit: Tree Leaf Complexity: Simple Leaf:
Fruit: Size Class:
Bloom InformationBloom Color: Yellow
Bloom Time: Mar , Apr , May
DistributionUSA: CA Native Distribution:
mostly in foothills of Coast Ranges & Sierra Nevada Native Habitat:
Dry, rocky slopes below 3500 ft.
Growing ConditionsWater Use: Low
Light Requirement: Sun
Soil Moisture: Dry
CaCO3 Tolerance: None
Soil Description: Dry, rocky soils.
Conditions Comments: Slow-growing. Drought-tolerant.
Oaks are most often propagated from seed. No pretreatment is necessary. Plant immediately – outdoors or in deep containers to accomodate long initial taproot. Many oaks require cold temperatures to initiate shoot
development. Protect outdoor beds with Seed Collection:
Best quality acorns are picked or shaken from the tree. Collect when color has changed to brown. Best if sown immediately as acorns lose viability quickly in storage. Short-term storage in moist, shaded saw dust or sand. Acorns to be sown immediately can be soaked in hot water for 15 min. to prevent weevil infestation. Stored seed should be fumigated with methyl bromide. Commercially Avail:
From the National Organizations Directory
According to the species list provided by Affiliate Organizations, this plant is either on display or available from the following:
Santa Barbara Botanic Garden
- Santa Barbara, CANative Seed Network
- Corvallis, OR
Record Last Modified: 2007-01-01
Research By: TWC Staff