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black walnut

black walnut (Juglans nigra)
Photo © Illinois Department of Natural Resources

Features and Behaviors

The deciduous black walnut tree may grow to a height of 150 feet and a diameter of five feet. The trunk is straight, and the crown is rounded. The bark is thick, black and deeply furrowed. The pith in the twigs is chambered, that is, divided by partitions. The bud is rounded at the tip, pale brown and hairy. The pinnately compound leaves have 15 to 23 leaflets and are arranged alternately on the stem. Each lance-shaped leaflet may be up to three and one-half inches long and one and one-half inches wide. The leaflet is toothed along the edges, yellow-green and smooth above and paler and hairy below. Leaves turn yellow in the fall. Male and female flowers are separate but located on the same tree. The male (staminate) flowers are arranged in yellow-green, hairy catkins, while the female (pistillate) flowers are in small spikes. Neither type of flower has petals. The spherical fruits are arranged in groups of one or two. Each green or yellow-green walnut may be up to two inches in diameter. The husk on the fruit is thick, while the nut is very hard, oval, dark brown and deeply ridged. The seed is sweet to the taste.

The black walnut may be found statewide in Illinois. This tree grows in rich woodlands. The black walnut flowers in April and May when the leaves are partly grown. Its hard, dark brown wood is used for making furniture, cabinets and in interior finishing. The nuts are used in cooking and as food by wildlife.

Illinois Range


​Kingdom: Plantae

Division: Magnoliophyta

Class: Magnoliopsida

Order: Fagales

Family: Juglandaceae

Illinois Status

​common, native

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