The English walnut’s wild cousin
Black walnut is a powerful plant. It is not well suited for domestic landscapes because of the heavy nuts that fall in Autumn; and because it repels other plants with a compound called juglone found in its roots, bark, leaves, and nut hulls. But there are lots of great reasons to have black walnut trees in your neighborhood.
It is best suited to open sites on rich, well-drained soil…old fields and edges of woods are ideal. In it’s native range, black walnut withstands temperatures well below zero degrees in some areas, as well as high humidity and ninety-degree days lasting four months or more in others. USDA zones 5-9 are good areas for black walnut.
Uses of the black walnut
The uses of black walnut are nearly endless. First and foremost (for me) is the nut itself. The kernel is similar in flavor to the English or Persian walnut, but much stronger. They are delicious in chocolate chip cookies, breads, pies, salads, stuffing, or plain right out of the shell. Black walnut is a good source of beta-carotene, calcium, iron, magnesium, manganese, phosphorous, potassium, selenium, silicon, zinc, B vitamins, and vitamin C. They are a rich source of Omega 3 and Omega 6 fatty acids. The nut shells are very hard, and have been used variously over the years for removing burrs on metal, removing paint, as a traction ingredient in tire-making, and lots of other creative and useful tasks.
Black walnut hulls are probably most widely known for their use in natural dyes and stains for hair, fabric, and wood. When ripe, they readily impart a deep brown color to whatever they touch. They have also been used in medicine to treat diphtheria, syphillis, intestinal worms and other ailments.
The wood is prized for use in all types of ornamental woodwork, furniture, floors, and gun stocks. It has highly varying color from creamy white sapwood to dark brown heartwood and the grain can be stunning. Less common is black walnut firewood. It makes an excellent firewood, but because of its many other values it is seldom burned.
While black walnut may not be your next back yard shade tree, keep it in mind. Its benefits are plentiful, and there may be more that are yet undiscovered. Happy gardening!