Black walnut (Juglans nigra) is a towering deciduous tree native to Eastern and Southern North America, from Southern Ontario to Georgia and Texas. Also simply called American walnut, the black walnut is an aesthetically pleasing native tree valued for its majestic appearance and the variety of functions it fills in a garden.
The black walnut is a stately tree that can give a sense of old world grandeur to a garden. The tree reaches a maximum height of 70 to 100 feet, producing a loose, open spread of a similar size. The wide spread of the walnut tree makes it ideal for a shade tree. The leaves, which may be up to two feet long, are pleasantly aromatic and change from green to pale yellow in the autumn. As the tree ages, the bark furrows into an attractive diamond pattern.
The black walnut tree is valuable for its resilience, because the tree is often disease and problem free if grown in the right conditions within its native range. Black walnuts do best in USDA zones 4 to 9 in a soil that is rich, moist and very well draining. The tree must have full sunlight to really thrive, but avoid planting it on an excessively hot south- or west-facing slope.
The timber of the black walnut is quite valuable and is considered one of the most important North American hardwoods. Walnut wood is used for gun stocks, fine toys and cabinetry, as well as veneered furniture. Growing walnut trees can be an investment, because the wood can be harvested and sold depending on market demand. A forester can provide advice on whether the timber of a walnut tree can be sold or not.
The black walnut tree produces oily, flavorful nuts that can be harvested and used in baking, salads or other dishes. One of the biggest perks of cultivating a walnut tree is enjoying the fresh nuts that it yields. Walnuts are rich in omega-3 fatty acids and contain a number of antioxidants. The nuts can be picked off the tree or the ground when the husk of the nut has turned to a yellowish black. Use gloves if necessary, as the casing of the nuts seeps out a powerful dye.
A healthy walnut tree will often produce more nuts than a family can bother to harvest and eat, but there are always squirrels or chipmunks to help out. A walnut tree provides food for wildlife and entertainment for those who enjoy watching the little rodents scurry about with the nuts. Squirrels often bury nuts, a practice that can help the valuable tree to spawn offspring if the animals don't come back to retrieve their bounty.