SelecTree: Tree Detail
BLUE OAK
Quercus douglasii
Photo Locations: Regional Parks Botanic Garden, Tilden Regional Park - Berkeley, CA, UC Berkeley Botanical Garden - Berkeley, CA, Hoyt Arboretum - Portland, OR and Los Angeles County Arboretum - Arcadia, CA
General Notes
A slow growing native oak. Commonly found on interior California hills.
Native to Central and Southern California.
A Quercus douglasii in Mariposa is registered as a California Big Tree. It measures 71 feet high, with a trunk circumference of 146 inches and a crown spread of 79 feet.
Family: Fagaceae
Tree Characteristics
Erect or Spreading with a High Canopy.
Rounded or Spreading Shape.
Has Deciduous foliage.
Height: 50 - 65 feet.
Width: 40 - 50 feet.
Growth Rate: 12 Inches per Year.
Longevity Greater than 150 years.
Leaves Oblong to Ovate, Bluish Green or Silver or Gray Green, Golden or Yellow or Orange, Deciduous.
Flowers Inconspicuous. Flowers in Spring. Has separate male and female reproductive parts on the same tree (monoecious).
Prolific, Brown Acorn, Medium (0.50 - 1.50 inches), fruiting in Fall or Winter.
Bark Light Gray, Furrowed, Scaly or Smooth.
Shading Capacity Rated as Moderate in Leaf.
Shading Capacity Rated as Moderate out of Leaf.
Litter Issue is Dry Fruit.
Tree Site Conditions & Constraints
Sunset Zones 3 - 11 and 14 - 24.
USDA Hardiness Zones 6 - 9.
Exposure Full Sun to Partial Shade.
Moist to Dry Soil.
Clay, Loam or Sand Texture.
Highly Acidic to Slightly Alkaline Soil pH.
Seaside Tolerance is Medium in Mild Zone.
Pests & Disease Information
Resistant to Verticillium. Susceptible to Caterpillars, Insect Galls, California Oak Moth, Gall Wasp and Scales, Crown Rot, Mistletoe, Armillaria, Brown Rot, Powdery Mildew and Root Rot.
Health, Safety & Environmental Concerns
Branch Strength Rated as Strong.
Root Damage Potential Rated as Low.
Allergy and Poisonous Health Hazard.
Biogenic Emissions considered Moderate.
Desirable Wildlife Plant.
Attracts Birds and Squirrels.
Deer Palatable.
Cite this tree:
SelecTree. "Quercus douglasii Tree Record." 1995-2021. Jan 21, 2021.
< https://selectree.calpoly.edu/tree-detail/quercus-douglasii >
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