English oak USDA PLANTS Symbol: QURO2
U.S. Nativity: Exotic
Habit: Hardwood Trees
Quercus robur L.

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Taxonomic Rank: Magnoliopsida: Fagales: Fagaceae
Synonym(s): pedunculate oak
Native Range: Europe, N. Africa, W. Asia (REHD);

Appearance
Quercus robur has a wide spreading crown, short sturdy trunk, and deeply fissured gray brown bark. It can grow to 140 ft (42.7 m) tall with a rounded spread of 80 ft (24.4 m) or more, but is usually smaller in cultivation. It is native to Asia and Europe.
Foliage
The small deciduous leaves, 3-5 in (7.6-12.7 cm) long, with 3-7 pairs of rounded lobes, and extremely short petioles. They remain deep green long into autumn before turning brown and then persisting on the tree well into winter.
Flowers
The flowers are hanging catkins which appear with the emerging leaves in early spring.
Fruit
The fruits are acorns which are elongate, about 1 in (2.5 cm) long, with a cup that covers 1/3 of the nut. They are born singly or in clusters of 2-5 which dangle on a single long 1-4 in (5.1-10.2 cm) peduncle.
Ecological Threat
Q. robur is easily grown in average, medium, well-drained soils in full sun. It prefers moist well-drained soils, but adapts to a wide range of soil conditions. Can take up to 25-30 years for this tree to bear a first crop of acorns.

Selected Images from Invasive.orgView All Images at Invasive.org


Tree(s); habitat
Robert Vidéki, Doronicum Kft., Bugwood.org
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Fruit(s); Acorns.
Gil Wojciech, Polish Forest Research Institute, Bugwood.org
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Plant(s); 1. Branchlet with young shoots, male (a, b) and female (c, d) inflorescences. Typically several female flowers develop with each long, slender peduncles. - 2. Branchlet with mature shoots and almost ripe fruits (acorns). - 3. Ripe acorn, at the end of the first season. - 4. Peduncle with empty cup (a) and aborted fruits (b, c). - 5. Winter-branchlet; buds are egg-shaped, roundish at the top. After Hempel & Wilhelm, 1889. Photos and explanations from the book: Zelimir Borzan. "Tree and Shrub Names in Latin, Croatian, English, and German, with synonyms", University of Zagreb, 2001.
Zelimir Borzan, University of Zagreb, Bugwood.org
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Bark;
Gil Wojciech, Polish Forest Research Institute, Bugwood.org
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EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.


Invasive Listing Sources:
Reichard, Sarah. 1994.  Assessing the potential of invasiveness in woody plants introduced in North America. University of Washington Ph.D. dissertation.