English Oak - Quercus robur
Family: Fagaceae - Beeches, Chinkapins and Oaks
Leaf type and persistence: deciduous. Leaf blade length: 4 to 8 inches; 2 to 4 inches. Fall color: copper. Flower color: brown. Flower characteristics: inconspicuous and not showy. Fruit shape: elongated; oval. Fruit length: 1 to 3 inches. Acorns attract squirrels and other mammals. Acorns and twigs cause considerable litter problems. Light requirement: tree grows best in full sun. Soil tolerances: clay; loam; sand; alkaline; well-drained. Drought tolerance: high. Aerosol salt tolerance: high.
 
although not widely used in the United States, English Oak appears to be very drought-tolerant and could be used more extensively, particularly in climates such as west Texas with low humidity where powdery mildew may not be a big problem. It also grows well in a wide range of soil from acid to alkaline. There are a number of cultivars for leaf color and crown form. The most popular is ‘Fastigiata’ which is distinctly upright or columnar, but varies in spread from 10 to 18 feet due to seedling variation. Leaves turn brown in the fall and persist into the winter. The tree is very tolerant of urban conditions and should be grown and used more often.

 


English Oak Foliage

An oak "hedgehog" gall on a white oak leaf. This growth is induced by a small cynipid gall wasp whose larva develops inside.

Several insects attack oak trees. They are usually not important but may become epidemic and kill weakened trees. Economically, the most important are the wood borers. These may damage the wood of standing trees and cause log and lumber defects. White oak is attacked by several leaf eaters including the gypsy moth (Lymantria dispar), orange-striped oakworm (Anisota senatoria), variable oakleaf caterpillar (Heterocampa manteo), several oak leaf tiers and walking stick. The Cynipid wasps cause galls to develop on the leaves, in the acorn or on the cup.

White oak also hosts various scale insects, gall-forming insects, and twig pruners, but most of these are of minor importance. White oak acorns are commonly attacked by insects, in some cases affecting half the total acorn crop. Weevils of the genera Curculio and Conotrachelus cause most acorn damage. Light acorn crops usually are more heavily infested than heavy ones. Two moths damage acorns, the filbert worm (Melissopus latiferreanus) and Valentinia glandulella.
 

 


This English Oak was started from acorn 75 years ago. It is nearly 100 feet tall.

Powdery mildew is often seen on much of the tree. The cultivar ‘Attention’ has a narrow crown and may be resistant to powdery mildew. Generally pest free, although mites can be seen on some trees. Powdery mildew can be a serious problem on English Oak in humid areas. Galls cause homeowners much concern. There are many types and galls can be on the leaves or twigs. Most galls are harmless so chemical controls are not suggested. Scales of several types can usually be controlled with sprays of horticultural oil. Aphids cause distorted growth and deposits of honeydew on lower leaves. On large trees, naturally occurring predatory insects will often bring the aphid population under control.

Boring insects are most likely to attack weakened or stressed trees. Newly planted young trees may also be attacked. Keep trees as healthy as possible with regular fertilization and water during dry weather. Many caterpillars including gypsy moth feed on Oak. Large trees tolerate some feeding injury without harm. Trees repeatedly attacked, or having some other problem, may need spraying. Tent caterpillars form nests in trees then eat the foliage. The nests can be pruned out when small. Where they occur, gypsy moth caterpillars are extremely destructive on Oaks.

Fall cankerworm has been a problem in some years. Twig pruner causes twigs to drop off in the summer. The larvae ride the twig to the ground. Rake up and destroy fallen twigs. Spider mite infested leaves first look dusty then yellowed, particularly on English Oak. Lace bugs suck juices from leaves causing them to look dusty or whitish gray. Leaf miners cause brown areas in leaves. To identify leaf miner injury tear the leaf in two across the injury. If the injury is due to leaf miner, upper and lower leaf surfaces are separate and black insect excrement will be seen.
 (United States Department of Agriculture NRCS Plant Fact Sheet ST-558)