Trees of Dickinson County: Black Walnut

Black walnut trees (Juglans nigra) are probably best known for two things --- their seed and their wood.

Although not as commonly eaten as an English walnut, what you would find in a grocery store, black walnuts can also be eaten if harvested, processed and stored correctly. They have an especially strong nut flavor that some people love!

The tree also is valued for its use for hardwood furniture and decor.

Size

Black walnuts grow 75-150 feet tall when mature.

Habitat

Black walnut trees grow well in mesic soil, in part shade to full sun.

Walnuts tend to take over an area, because their roots contain juglone, a toxic substance that kills off susceptible plants.

Leaves

Black walnut leaves are once-pinnately compound, alternate each other instead of opposite each other on stalks 1-2 feet long with 11-23 leaflets. They are ovate-lanceolate-shaped, 2-4 inches long and finely toothed. The surface of each leaf is hairless but the bottom is hairy.

Leaves are a golden yellow in the fall.

Seeds

Trees begin to bear fruit in 12-15 years. They are partially self-fertile, but having multiple trees in an area helps with pollination.

The hard-to-crack shell encases the nut. Beware, crushed shells can stain fingers, clothing and even concrete.

Fox squirrels especially love black walnuts, as do other wildlife.