Quercus petraea
Common name: 
Sessile Oak
Durmast Oak
Irish Oak
kwer-KUS pe-TRE-a
Native to (or naturalized in) Oregon: 
  • Deciduous tree, to 150 ft (45 m) tall, but in stormy exposed sites only 33-50 ft (10-15 m), forms a broad, rounded crown; trunk reaches far into the crown. Leaves alternate, simple, 6-17 cm long and 6-9 cm wide, obovate, glossy green above, beneath it is pale and smooth to pubescent, 4-6 pairs of rounded lobes, the base is broadly wedge-shaped (cuneate) to truncated; petiole is 1-1.5 cm long, usually yellow.  Acorns are clustered, 2-3 cm long, stalkless (sessile), ovoid to ovoid-oblong, enclosed about 1/3 by the cup; they mature the first year.
  • Sun to part shade, grows well in deep, fertile soils.
  • Hardy to USDA Zone 4             Native to Europe, including Ireland (its National Tree), Britain, from Norway south and east to Spain, S.W. Russia and Greece. Often found on shallow, well-drained and acidic soils.
  • petraea:  rock-loving,  the name apparently reflects the native trees preference for rockier areas of England. 
Click image to enlarge
  • plant habit

    plant habit

  • foliage


  • expanding leaves

    expanding leaves

  • leaves


  • developing acorns

    developing acorns