Northern Red Oak

Size, growth and what to expect

Northern red oak grows fast for an oak, about 2.75 feet a year in our growth estimator. Expect 50 to 75 feet with a crown as wide. Forest trees on good sites stand 65 to 98 feet, and the tallest pass 160 feet. Under good conditions a tree may live 500 years.

It flowers in April or May, and the acorns ripen from late August to late October of their second year. Trees first bear at 20 to 25 years and bear heavily from 40 or 50, with good crops every 2 to 5 years. Trees with large, uncrowded crowns bear the most. The acorns are three quarters of an inch to an inch and a quarter long, with a flat cap over a quarter of the nut. Squirrels, deer, wild turkeys, jays and black bears eat them. The leaves turn russet to bright red in fall.

It grows wild from Nova Scotia and Quebec west to Minnesota and south to eastern Oklahoma, Alabama and Georgia. Outlying stands grow in Louisiana and Mississippi. It does best on the lower and middle slopes of north and east faces, in coves and on well-drained valley floors.

How to grow Northern Red Oak

Northern red oak wants full sun or part shade and a deep, well-drained, acid soil, at its best a sandy or silty loam. Once rooted it takes drought, dry soil and city conditions, and it tolerates some salt and polluted air. A soil that is not acid enough yellows its leaves. 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. Northern red oak transplants easily, and bare-root saplings set out in early spring survive far better than those planted in fall. Plant while dormant, 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. Red oak acorns need a winter before they sprout, and they die if they dry out. Sow them in fall an inch deep under hardware cloth. For spring, hold them damp in the refrigerator for 30 to 45 days first.

Water every week or two through the first summer, then only in a long drought. Deer and rabbits browse young oaks, so guard each sapling with a tube or cage for its first three years. Young trees tend to fork, so keep one central leader.

The flowers are wind pollinated, and an acorn crop wants another oak nearby. As a red oak it is susceptible to oak wilt, which can kill a tree within a few months, so prune only in the dormant season, to avoid the beetles that spread it. The spongy moth is its most destructive defoliator, and oak decline has struck it across much of the central Appalachians. Weevils, moths and gall wasps spoil many acorns, and in a poor year insects can take the whole crop.