Black walnut is an eastern North American form of walnut and perhaps the most adaptable species of its genus. It is an extremely valuable timber tree.
Description of black walnut: The black walnut is a large tree, often more than 100 feet in height, usually developing a full, well-formed trunk with high branches. The oval crown is quite open. The black trunk and stems add to its winter charms. The large, deciduous leaves are pinnately compound. Its nuts are edible but encased in a thick green covering that stains the skin, making harvesting difficult.
How to grow black walnut: It is best to grow this tree from seed, since it has a deep taproot and resents transplanting. The black walnut is fast-growing in its youth, so it makes an interesting landscape specimen within a reasonable length of time, and then its growth slows down. It rarely reaches its maximum height of more than 100 feet in culture unless it is supplied with a deep, rich, moist soil. It also grows well, but slowly, in dry soils.
Uses for black walnut: Due to its large size, the black walnut is best used as a specimen tree. Although tolerant of street conditions, it makes a poor street tree because of its messy leaves and fruit. All walnuts produce juglone, a substance that can be toxic to plants growing in their vicinity.
Black walnut related varieties: The variety 'Laciniata,' with finely cut leaves, is the best choice for landscape use.
Black walnut related species: The English, or Persian, walnut (Jungians regain) produces the walnut of commerce, but it is of limited hardiness. The Carpathian walnut (J. regain 'Carpathian') is a hardier selection (zone 5).
Scientific name for black walnut: Juglans nigra