Black Walnut
Juglans nigra L.

Black Walnut: Full Size

Mature Size: 50 to 90 feet in height and 2 to 3 feet in diameter.

Form: Straight, clear trunk with a narrow crown and thick twigs and branches.

Habitat: Deep, well-drained soils; grows best in rich bottomlands, moist coves and stream sides; grows best on the lower north- or east-facing slopes.

Leaves

Black Walnut: Leaves

Alternate, pinnately compound, 12 to 24 inches long, with 10 to 24 sharply oval, finely toothed, long-pointed leaflets 3 to 3½ inches long; bright, clear yellow in autumn.

Flowers

Black Walnut: Flower

Yellow-green; males in catkins 2½ to 5½ inches long; females on short spikes near twig ends.

Fruit

Black Walnut: Fruit

Round, 2 to 2½ inches across, with a thick, green, non-splitting husk; nut inside is furrowed and hard; matures in late summer to fall.

Bark

Black Walnut: Bark

Thick, dark brown to black, ridged and furrowed with a deep diamond pattern.

Twigs

Thick, light brown, with a buff-colored chambered pith inside; buds tan, large, with a few fuzzy scales; leaf scars 3-lobed, resembling a "monkey face."

Values and Uses

The heartwood is heavy, hard and strong, with a rich chocolate-brown color of superior quality and value. It is prized for veneer, fine furniture, paneling, cabinetwork and gun stocks. The nut shells are ground into an abrasive cleaning agent for jet engines, filler for dynamite, a filter agent in smokestacks and a flour-like carrying agent for insecticides. Squirrels, birds and people eat the sweet, oily nuts. Sapsuckers drill rows of holes to feed on the sap. Mice and rabbits eat the bark of young trees, and deer browse on the buds.

Did You Know?

Black walnut trees secrete a toxic chemical called juglone, which prevents many other species from growing near them.