Genus and SpeciesQuercus douglasii 
Common Name: Blue Oak 

Habit and Cultural Information:

Type:  Deciduous
Category:  Tree
Origin:  California
Height:  30 – 50 feet
Width:  30 – 50 feet
Form:  Low branching, wide spreading
Water Needs:  Drought tolerant once established
Sunset Western Garden zones:  3-11, 14-24
Winter Hardiness:  -5
Exposure:  Full sun
Foliage:  Bluish green
Fruit or Seed:  Acorns from September to November
Bark:  Light grey, shallowly checked in small squares

Other Details:  The Quercus douglasii can be found in the foothills surrounding the central valley of California. The name Blue Oak derives from the exquisite dark-blue tint of its leaves which are deciduous. Although slow growing, some trees are reported to be over 500 years old however, most are less than 300 years old. The Quercus douglasii or Blue Oak is appreciated for its natural, interesting shape and interesting branch structure against the winter sky and most often grows wider than tall.