Quercus lobata
Common name: 
Valley Oak
Roble Oak
California White Oak
kwer-KUS lo-BAH-tuh
Native to (or naturalized in) Oregon: 
  • Broadleaf, deciduous, medium to large tree, at maturity from 30-90 ft tall and 2-4 ft wide (9-27 m × 0.6-1.2 m), but sometimes much greater.  Branches have an irregular, spreading and arching habit. The trunk is usually short and stout; bark is light gray and in time segments into rectangular, alligator-like, patches.  Leaves are simple, alternate, obovate, 5-10 cm long, base wedge-shaped, 6 to 10 rounded or blunt lobes, separated by deep clefts (greater than ½ distance from lobe tip to midrib); dark green above and paler green below and covered with a fine pubescence.  Inconspicuous male and female flowers appear in spring and are borne on the same tree (monecious).  Male flowers are in yellow-green catkins about 2.5 to 5 cm long whereas the small female flowers are usually in clusters of 2-3 in axils of leaves.  Fruit, an acorn, is brown, slender, 3-6 cm long, pointed ("shaped like a pointed cartridge shell", Peattie, 1953), 1/3 of which is enclosed in a deep cup with light brown scales; matures in first year.
  • Full sun to patial shade, a minimum of four hours direct sunlight per day, best in deep soils where it can tap ground water
  • Hardy to USDA Zone 7   Native range is limited (endemic) to and widely distributed in California; it is common in the Central Valley and found in many smaller valleys and also in the coastal hills and mountain ranges.  It tolerates cool wet winters and hot dry summers, but requires abundant water.
  • lobata: lobed, the leaves
  • Salem, Oregon: Bush's Pasture Park, on Mission Street

 A majority of the photos by Steven Ruettgers, Bakersfield, CA

Click image to enlarge
  • plant habit, in habitat

    plant habit, in habitat

  • plant habit

    plant habit

  • plant habit

    plant habit

  • spring growth, young leaves and male catkins

    spring growth, young leaves and male catkins

  • leaves, silhouette

    leaves, silhouette

  • leaf


  • leaves


  • developing acorns

    developing acorns

  • immature acorns (S. Ruettgers)

    immature acorns (S. Ruettgers)

  • acorn


  • mature acorns

    mature acorns

  • trunks, 20-30 yr-old trees

    trunks, 20-30 yr-old trees

  • bark, 20-30 yr-old tree

    bark, 20-30 yr-old tree