SelecTree: Tree Detail

BLUE OAK
Quercus douglasii

Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii Quercus douglasii 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.

Oval, Rounded or Umbrella 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, Blue Green, Bronze, Gold, Orange or Multicolored, Deciduous.

Flowers Inconspicuous. Flowers in Spring. Has separate male and female flowers 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, Oak Root Rot, 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." 1995-2017. Dec 11, 2017.
< http://selectree.calpoly.edu/tree-detail/quercus-douglasii >

SelecTree Nursery Connection Map
Cal Poly / ESRI