Black Walnut Plant Features

Tree Description

• Black walnuts are medium-sized trees and generally average 70 to 90 feet tall, though they can grow to 150 feet. The bark is brown to gray-black in color, with diamond-patterned furrows and ridges. Twigs are light brown to orange, and the tree flowers in May or June. The fruits ripen in October and have a light green husk surrounding a black nut. The nut has a corrugated appearance with rounded ridges.

Habitat

• Black walnut trees are fairly scarce but can be found scattered throughout the central and eastern areas of the United States. Naturally, the tree's range extends from western Vermont and Massachusetts to central Michigan, southern Ontario, eastern South Dakota, southern Minnesota, northeast Nebraska, central Texas and Oklahoma, Georgia and northwest Florida. It is most abundant in Kansas. Black walnut trees grow best in rich, well-drained soil and are hardy to U.S. Department of Agriculture plant hardiness zones 4 through 9.

Uses

• Many native groups used the bark of the black walnut tree medicinally, both as a laxative and a cure for toothaches. It was also used to make colored dyes. The leaves and fruit husks of the plant were used by the Comanches as a treatment for ringworm. Native Americans also tapped the trunk of the tree to produce syrup. The distinctive flavor of black walnut fruits makes it a popular addition to ice cream, cakes and candies. The wood is prized by carpenters, but because of its scarcity, it's now used mainly as a veneer.

Growing Black Walnut Trees

• It is difficult to transplant black walnuts, so they should ideally be grown from seed. Black walnuts prefer full sun sites and thrive in moist, well-drained soil that is rich in organic matter. Black walnuts adapt to their environment by producing a toxin called juglone that inhibits the growth of surrounding plants. The trees may self-pollinate, although two trees should be planted to ensure pollination.