White Oak

Size, growth and what to expect

White oak grows slowly, about a foot a year in our growth estimator. In a yard expect 50 to 80 feet with an equal spread, while forest trees often reach 80 to 100 feet. Individual trees have stood 150 feet tall and lived 600 years.

It flowers from late March to late May as the leaves open, and the acorns ripen in a single season, dropping in September and October. Open-grown trees can bear at about 20 years, but forest trees seldom bear before 50, and good crops come only every 4 to 10 years. The acorns are three quarters of an inch to an inch long, a quarter covered by a warty cup. Low in tannin, they are a choice food of deer, turkeys, blue jays, wood ducks, squirrels and black bears. People have eaten them too, once boiled or soaked to leach out the bitterness.

It grows wild from southwestern Maine and southern Quebec west to southeastern Minnesota, and south to eastern Kansas, Texas and northern Florida. It is absent from the high Appalachians and the lower Mississippi Delta.

How to grow White Oak

White oak wants full sun or light shade and a deep, well-drained soil on the acid side. It grows in clay, loam, sand or rocky ground and stands dry spells once rooted, but not wet ground or alkaline soil, where its leaves yellow. Its roots suffer from compaction, fill and trenching, so plant it where no digging or paving will reach them. Set trees 50 feet apart, and keep each one 40 feet from a wall and more than 50 feet from overhead wires.

Saplings ship bare-root or potted. The taproot makes an older tree hard to move, so plant it young and plant it once. Plant from leaf fall until bud swell, in a hole wider than the roots and no deeper. Set the root flare at the soil line, put the native soil back in, and keep the mulch clear of the trunk. White oak acorns sprout soon after they fall and die if they dry out. Sow them on arrival, an inch deep, under hardware cloth. The root goes down that fall, and the shoot waits for spring.

Water every week or two through the first summer, then only in a long drought. Deer browse young oaks and rabbits can girdle the stems, so guard each sapling with a tube or cage for its first three years. Keep one leader while the tree is young, and prune only in the dormant season.

The flowers are wind pollinated, and an acorn crop wants another oak nearby. Its pollen seldom travels more than about 650 feet, so keep the other oak within that distance. As a white oak, it ripens its acorns in one season, and they sprout as soon as they fall. It suffers far less from oak wilt than the red oaks and may lose only a limb at a time, but prune in the dormant season all the same. Weevils and the larvae of two moths ruin many acorns, in some years half the crop, and light crops suffer most. A tree stripped by caterpillars can die when a root fungus and the two-lined chestnut borer follow.