Tree Description:
A large tree to 100 feet tall and a trunk to 3 feet or more, with a straight stem often clear of branches for half of its height, and an open, rounded crown of foliage.
Range/Site Description:
Occurs in East Texas on rich bottomlands and moist fertile hillsides, as far west as the San Antonio river.
Leaf:
Alternate, once-compound, 12" to 24" long, yellowish-green in color, pubescent beneath, consisting of 15 to 23 leaflets, each 3" to 5" long and 1" to 2" wide, the largest ones in the middle of the leaf, finely-toothed along the margin and tapering to a long point at the tip.
Flower:
Male and female flowers borne separately on the same tree in early spring; the male flowers as stout, greenish-yellow catkins 2" to 5" long; female flowers occur in groups of 1 to 4 on new growth at the end of twigs.
Fruit:
A large, round nut, borne singly or in pairs, 1.5" to 2.5" in diameter, enclosed in a solid green, leathery husk that does not split even after ripening; the nut is black, with a thick, hard, finely-ridged shell that holds the oily, but edible, kernel.
Bark:
Thick, dark brown, with blocky or rounded ridges divided by deep fissures. The trunk, branches, and leaves are free of prickles or thorns.
Wood:
The chocolate-brown heartwood is heavy, hard and strong, and is surrounded by a thin band of cream-colored sapwood. The wood is free from warping and checking, takes a high polish, and is durable, making it highly prized for furniture, cabinet work, and gunstocks.
Similar Species:
Arizona walnut (Juglans major) has fewer leaflets, a smaller fruit and nut, and a more western distribution.
Interesting Facts:
Black walnut releases a chemical compound from its roots, called "juglone," into the soil which inhibits the growth of nearby plants. This property is called "allelopathy" and plants that do this are called "allelopathic."
