Quercus douglasii Hook. & Arn.
Fagaceae (Beech Family)
USDA Symbol: qudo
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.
From the Image Gallery
Plant CharacteristicsDuration: Perennial
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Venation: Pinnate
Breeding System: Flowers Unisexual , Monoecious
Fruit Type: Nut
Size Notes: Up to about 50 feet tall.
Bloom InformationBloom Color: Yellow
Bloom Time: Mar , Apr , May
Native Distribution: Throughout CA, 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.
PropagationDescription: 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: yes
Find Seed or Plants
Find seed sources for this species at the Native Seed Network.
View propagation protocol from Native Plants Network.
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Santa Barbara Botanic Garden - Santa Barbara, CA
Native Seed Network - Corvallis, OR
BibliographyBibref 841 - Native Alternatives to Invasive Plants (2006) Burrell, C. C.
Search More Titles in Bibliography
Web ReferenceWebref 3 - Flora of North America (2014) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Additional resourcesUSDA: Find Quercus douglasii in USDA Plants
FNA: Find Quercus douglasii in the Flora of North America (if available)
Google: Search Google for Quercus douglasii
MetadataRecord Modified: 2022-09-23
Research By: TWC Staff