Quercus douglasii
Common name: 
Blue Oak
California Blue Oak
KWER-kus dug-LAS-e-i
Native to (or naturalized in) Oregon: 
  • Deciduous tree, typically 20-60(90) ft [6-18(27) m] tall, rounded top, short stout branches, ascending or horizontal, in the open the trunk may be short and foliage may reach the ground; shrubby in southwestern part of its range.  Bark light gray and checkered into small squares.  Leaves alternate, simple, 4-10 cm long with 5-7 irregular lobes, lobe sinuses are usually shallow, some leaves may be entire, dull bluish-green above and pale bluish-green below; fall colors are light pink, orange and yellow.  Fruit (acorn), the nut is brown when ripe, egg-shaped, about 2-3 cm long, sharply pointed tip, acorn cups are saucer-shaped, 12-15 mm wide.
  • Sun.  Drought resistant, best in sandy soil, tolerates coastal winds.
  • Hardy to USDA Zone 8?       Native to the dry woodlands and valleys around the California's Central Valley and the interior valleys of southern California.
  • Portland, Oregon: Hoyt Arboretum
Click image to enlarge
  • plant habit (Steven Ruettgers)

    plant habit (Steven Ruettgers)

  • plant habit

    plant habit

  • canopy


  • leaves


  • leaves, underside

    leaves, underside

  • leaves and young acorns (Steven Ruettgers)

    leaves and young acorns (Steven. Ruettgers)

  • developing fruit (acorn)

    developing fruit (acorn)

  • trunk, bark

    trunk, bark