Oaks Quercus alba

The white oak is a large deciduous, hardwood tree is slow growing and can reach heights of 135 feet with an 80-foot spread but generally tops out at 80 to 100 feet. Young trees are typically pyramidal in form, but as the tree matures it has a rounded and broad crown. The distinct feature of this tree is its fingerlike lobed leaves with rounded tips and no bristles. Their fall foliage color is dark reddish to brown. The male flowers are the showiest, and the female flowers are inconspicuous. The fruit is a 3/4- to 1-inch-long brown acorn with a lumpy cap. This tree is a member of the Fagaceae or beech family and is the most important lumber tree of the white oak group.

The white oak is a native to the eastern United States and is usually found in forested areas of dry slopes, valleys, and ravines.

The genus name, Quercus, is the Latin name for oak trees. The epithet, alba, means white. This refers to the bark's ash-gray bark color. The common name is a reference to the color of the finished wood, not the bark.  

The white oak prefers full sun to partial shade in coarse, deep, moist, well-drained, loamy, slightly acidic soil but is adaptable to other soil types and is fairly drought tolerant once established. Wet sites should be avoided. The deep taproot makes it difficult to transplant. The tree is propagated by seeds.

The bark is light ashy gray with vertical blocks and scales. The lobed and rounded tip leaves are green on the upper surface and glaucous beneath. The male flowers are pendulous yellowish-green chains that occur in clusters. The reddish female flowers appear on short stalks about 5 to 10 days after the male flowers. Both emerge shortly after the leaves in the spring. The female flower produces the acorn which is initially green and ripens to a tannish brown. 

This is a long-lived tree is a prolific supporter of wildlife for food and habitat. It supports a wide variety of butterflies and moths plus small mammals and songbirds. The acorns of white oak are edible (to humans) after tannins are leached or boiled out.  

Use white oak as a shade tree for large yards or parks, or in a naturalized area for wildlife to enjoy. It is suitable for butterfly, children’s, drought-tolerant, edible, native, nighttime, and pollinator gardens. However, it should not be planted near structures or pavement due to its eventual size. It is also toxic to horses.

Seasons of Interest:

Bark:  Winter         Foliage:  Spring, Summer, and Fall               Fruits:  Fall

Quick ID Hints:

• deciduous tree, pyramidal in youth, broad, rounded with age
• light ashy gray scaly bark with vertical block and scales
• the leaves are green, elliptic with rounded or fingerlike lobes without bristles
• pinnately lobed leaves with entire margins, widest typically at the middle, glaucous on the undersides
• male flowers prominent pendulous long yellowish-green chains arranged in clusters
• reddish female flowers appear on stalks and are smaller and less showy
• fruits are 3/4- to 1-inch-long acorns, initially green and ripen to tan, brown with a lumpy cap that covers 1/4 to 1/3 of the nut

Insects, Diseases, or Other Plant Problems:  Numerous insect and disease pests, but the damage is rarely significant. The white oak is susceptible to oak wilt, anthracnose, cankers, leaf spots, powdery mildew, and oak leaf blister. Potential pests include scales, oak skeletonizer, leaf miners, aphids, galls, and lace bugs. Chlorosis can occur if the pH in the soil is too high, resulting in iron deficiency. White oak is sensitive to soil compaction and susceptible to wind damage. It can be messy.

VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens.