English Oak - Quercus robur

English Oak - Quercus robur
Family: Fagaceae. English Oak is a massive, majestic tree once used extensively for sailing ship construction.
A very slow-growing tree, it has been known to live 700 years or more.
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English Oak

English Oak Foliage

English 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.

Young English Oak (18 years old, grown from acorn)

Young English Oak foliage in spring colors

in spring colors, May 3rd, near Chicago

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.

Acorn Weevil, Curculio sp.

Oak Borer Beetles, Agrilus sp.

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 at The Morton Arboretum was started from acorn 75 years ago. It is about 65 feet tall.

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

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