Quercus glauca
Common name: 
Japanese Blue Oak
Ring-cupped Oak
Pronunciation: 
KWER-kus GLAW-ka
Family: 
Fabaceae
Genus: 
Quercus
Synonyms: 
Cyclobalanopsis glauca
Type: 
Broadleaf
Native to (or naturalized in) Oregon: 
No

  • Broadleaf, evergreen, live-oak, tree to 20-30 ft (3-10 m) tall, it may reach over 50 ft (13 m) in its native habitat, upright-oval to rounded form.  Leaves simple, alternate, elliptic-lanceolate, 7-15 cm long and 3-6 cm wide, dull green and hairless above, whitish pubescent below, margin entire or serrate on the upper half; new leaves have a silky-pubescence and are bronzy or purplish-green.  Yellowish-green flowers are in separate male and female catkins which appear in spring, inconspicuous.  Acorns are 1–1.5 cm long, brown, with a series of concentric rings on the outside of the acorn cup (called a "ring-cupped oak").

  • Sun to partial shade, best in rich, humusy, medium moisture, well-drained soils
  • Hardy to USDA Zone 7   Its native range extends from the Himalayas eastward to China, Japan and Korea. 
  • glauca: having a bloom, a whitish coating,  (possibly a reference to the pubescent on new leaves)
Click image to enlarge
  • plant habit

    plant habit

  • leaves

    leaves

  • leaves, underside

    leaves, underside

  • trunk, bark

    trunk, bark