Identifying Characteristics
| Size/Form: | Black walnut is a medium-sized tree, growing 70 to 130 feet in height and 2 to 4 feet in diameter. In dense stands, it commonly produces a long, clear bole that supports a small, narrow, open crown. Grown in the open, it develops a short trunk and a massive, spreading crown. The root system of this tree is deep and widespread. |
| Leaves: | The leaves are pinnately compound, alternate, and deciduous. They generally have 15 to 23 leaflets on a central stalk 47 inches long. Leaflets are oval and tapered, growing 3 to 4 inches in length and 1 inch wide with acute apices. Leaflet bases are usually rounded. The middle leaflets are larger than those at either end of the leaf, with the terminal leaflet either small or missing. The top of the leaflet is smooth and yellowish-green while the underside has hairs. The leaflet margins are finely serrate. The rachis is hairy. |
| Twigs: | The twigs are stout, brown to orange-brown. The pith is yellowish-gray and chambered. |
| Bark: | Light brown and scaly when young. As the tree matures the color becomes a dark gray-brown to almost black with rounded intersecting ridges and deep furrows. The inside of the ridges is chocolate brown. |
| Flowers: | Black walnut is a monoecious species. The male flower is a single-stemmed catkin, 2 to 5 inches long. The yellow-green female flower exists on short spikes near the twig end and blooms in late spring. |
| Fruit: | A round, globular nut, up to 2 inches in diameter that is enclosed in a thick, succulent, yellowish-green husk. They are found in clusters of one to three. The seed is oily, sweet, and edible. |
Similar Trees on the Florida 4-H Forest Ecology Contest List:
The fruit of black walnut is distinctive, but you can't rely on always having it available. Several other plants on our list also have alternate, pinnately-compound leaves. |
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