The Black Walnut (Juglans nigra L.) is a deciduous tree that is native to eastern North America. Black Walnut's range is extensive, preferring the fertile, moist, well-drained soils of bottomlands and lower slopes, from southern Ontario, Canada west to southeast South Dakota, south to Georgia and southwest to central Texas. Iowa is a leading producer of walnut timber which is the single most important tree in terms of price per tree.

            Noted as the finest lumber in North America, this wood was shipped to England from Virginia as early as 1610.The Black Walnut was introduced into Europe in 1629. It is cultivated there as a forest tree for its high quality wood.

In ideal conditions Black Walnut trees will reach 150 feet tall with a diameter of 6 feet, but more commonly it will mature at 100 feet in height with a very straight trunk with a diameter of 3 feet and a broad, rounded, rather open crown.

            Black Walnut is highly prized for its dark-colored true heartwood. It is heavy and strong, yet easily split and worked. Walnut wood has historically been used for gunstocks, furniture, flooring, coffins, and a variety of other woodworking products. It is so valuable that so-called "Walnut Rustlers" have been known to harvest it illegally by posing as forestry officials, cutting trees during the night, and even using helicopters to take them away quickly; such overharvesting has greatly reduced its numbers and range since colonial times.

   The leaves are 1 to 1.5 ft long with 11 to 23 alternate, finely-toothed, short-stalked, yellow-green leaflets which are smooth above and faintly hairy beneath. The terminal leaflet is often suppressed so that the leaf ends in 2 leaflets.

Male flowers are borne in catkins and female flowers in clusters.

The fruit of the Walnut tree is a round nut in a hard, corrugated shell. The shell is surrounded by a thick, slightly hairy, semi-fleshy husk which is yellow-green, turning black and once used by pioneers to make dye.

            The nuts of the Walnut tree make up 10% of squirrels' diet and they help to disperse the seeds. Red-bellied woodpeckers and beavers also eat the nuts, and the strongly flavored, oily kernel makes it commercially important for baking and flavoring.

Black walnut bark is dark gray or black and furrowed with deep, interconnecting ridges that become blocky.

           The root system is deep, wide-spreading, usually with a tap root. A toxic substance, Juglone, is leached from the roots and fallen leaves, inhibiting the growth of many plants, including young walnut seedlings. Walnut trees are rarely planted as lawn trees-they require exacting soil conditions, are subject to wind and ice damage, produce messy fruit and the toxic substance from their leaves may kill some ornamentals in the vicinity.

            Diseases which affect walnuts include a walnut anthracnose fungus (which causes severe defoliation and canker of stems), wilt, blight and witches' broom. Aphid, walnut caterpillar and walnut scale are the known insect pests of walnut trees.

            Whether straight or figured grain, Black Walnut is still the Aristocrat of the Native American hardwoods and the hallmark of tradition.