Black Walnut Tree

Botanical Name: Juglans nigra

Alternate Name: American Black Walnut, Eastern Black Walnut 

The Black Walnut (Juglans nigra) tree is a stately, large deciduous tree with a rounded or oval growth habit. Mature trees tend to have an absence of lower branches, with the canopy starting higher up the trunk. The Black Walnut naturally grows in eastern North America. It grows to a height of 75-100 feet with a spread of 75-100 feet.

The Black Walnut tree has a relatively short growing season – being one of the latest to leaf out in the spring and one of the first to drop its leaves in the fall. The foliage is pinnately compound and can grow up to 24 inches in length. Each leaf contains approximately 13-23 lanceolate to oblong shaped leaflets. Often the terminal leaflet can be missing. The leaves turn bright yellow in the fall, providing a stunning autumn display.

The attractive dark gray bark of the Black Walnut tree forms beautiful diamond shapes from its vertical ridges and fissures. The tree can make a striking silhouette in the winter months.

The male flowers of the Black Walnut are hairy catkins that droop from the tree, and the female flowers are more upright, growing on short spikes. The female flowers are followed by the edible nuts in fall, which are encased in a light green covering. The covering rots away when the fruits drop, leaving the hard shells protecting the nuts. These fruit are edible to wildlife and people and are grown and harvested commercially.

The Black Walnut tree’s roots produce juglone, a substance that is allopathic, which inhibits other plants from growing under it. This tree thrives in full sun and will not tolerate any shade. 

No serious disease or insect problems, but these trees may occasionally get leaf spot or anthracnose, bacterial blight, root rot, leaf spot, or twig dieback. Nut drop in the fall can cause a mess and stain concrete.


Height: 75-100 ft.

Width: 75-100 ft.

Shape: Oval, Rounded

Flower Color: Yellowish-Green

Flowering Time: May-June

Fall Color: Yellow

Features: Edible nuts, impressive shade tree

Exposure: Full Sun

Watering: Moderate & Regular

Soil: Prefers rich, moist and well-drained soil.

Growth Rate: Moderate

USDA Zones: 4-9

Uses: Shade tree, fruit tree

Similar trees: Assimina triloba, Carya ovata