Common Oak Quercus robur

English Oak is a large, broadleaf deciduous tree that is a member of the white oak group. This tree has a broad-spreading, rounded crown, and grows 40 to 70 feet tall and equally as wide. The trunk of the tree is short, rounded, and sturdy, and the bark is grayish-brown to black and deeply fissured. The flowers are separate male and female catkins that emerge in the spring as the leaves appear. The leaves are alternate, dark green, small, and measure only 3 to 5 inches long. They have 3 to 7 pairs of deeply rounded lobes. The distinguishing feature of the leaf is the small auricular or "ear-like lobes" at the leaf base. The fruits are oval, 1-inch-long acorns that appear on a long stalk. The cup or cap covers about 1/4 to 1/3 of the acorn. 

The English Oak is native to woodland areas from the British Isles to the Caucasus. It was brought to North America in the 1600s from Europe and has been an important lumber tree for furniture and shipbuilding. It is now found in the eastern and northwestern United States and southeastern and southwestern Canada. It is thought to be potentially invasive in some natural areas of the United State, but reportedly actual naturalization is rare. It may be found along roadsides, pastures, edges of forests, and woodlands.

The genus name, Quercus, is the Latin name for oak trees. The specific epithet, robur, is Latin and means "robust' and references the strength and hardwood of this tree.

This tree prefers moist, well-drained, loam soils, and full sun. It will adapt to a wide range of soil types and conditions. This tree is susceptible to powdery mildew in humid climates.

The leaves of the English Oak closely resemble the White Oak. The English Oak has shorter petioles and small auricular lobes at the base of the leaf. The stalks on the acorns are thin and longer than the White Oak. It may take 20 to 30 years for the English Oak tree to bear its first acorns.

It is a host plant for the larvae of the Imperial moth (Eacles imperialis), as well as numerous butterflies, including Banded hairstreak (Satyrium calanus), Edward's hairstreak (Satyrium edwardsii), Gray hairstreak (Strymon melinus), White-m hairstreak (Parrhasius malbum), Horace's duskywing (Erynnis horatius), and Juvenalis duskywing (Erynnis juvenalis).

English oak is considered to be a low-maintenance tree with few problems. It's an excellent specimen or shade tree for large lawns, parks, and public areas. The cultivar, 'Fastigiata,' or Upright English Oak is commonly used in the landscape because of its columnar habit.

Seasons of Interest:

Bark:  Winter  Bloom:  Spring   Foliage:  Spring, Summer, and Fall    Fruits: Fall, after tree age is 25 to 30 years old

Quick ID Hints:

• large deciduous tree, 40 to 70 feet tall and equally as wide
• grayish-brown to black bark with fissures, furrows, and ridges
• small, dark green leaves with 3 to 7 pairs of deeply rounded lobes and small auriculate lobes at the base of the leaf
• bluish-green on the undersides of the leaf and has a short petiole
• yellowish-green male and female catkins emerge in the spring with the leaves
• oval acorns measuring 1 inch long and appear on 1 to 3-inch long stalks and have a cap that covers 1/4 to 1/3 of the acorn

Insects, Diseases, and Other Plant Problems: The insects that may potentially be found on the English Oak include scales, oak skeletonizers, leaf miners, galls, oak lace bugs, borers, caterpillars, and nut weevils. Oak trees are susceptible to a large number of diseases. Oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots, and powdery mildew may occur.

The English Oak is known to have escaped and seeded in the landscape in British Columbia. Ontario, Nova Scotia, Maine, New Hampshire, Massachusetts, New York, Pennsylvania, and Ohio.