black walnut

Black walnut (Juglans nigra) is a North American flowering tree that is related to the hickory. Dendrologists, and others who fancy deciduous plants and trees, appreciate the fact that these stately giants are outstanding shade providers. However, there is a long-standing belief that black walnut trees also protect the home from lightning strikes. While some believe this is due to the presence of an abundance of minerals in the timber that act as electrical conductors, it may also be due to the fact that mature black walnut trees can reach up to 60 feet in height. Whatever the reason, these trees have apparently saved many abodes from disaster since it was once commonplace to adopt a strategy of planting groves of them in proximity. In fact, the next time you visit a historic residence or farmstead, conduct a visual scan of the property. Chances are you’ll see several black walnut trees standing ready to deter misfortune. As an added bonus, early homesteaders knew that the presence of black walnut on a potential stake of property indicated that the land was fertile since these trees require a rich, slightly alkaline, and well-drained soil in order to thrive.

The hardwood of black walnut is highly valued for its exceptional beauty and durability. The wood is particularly dense, yet it splits readily and is easier to machine than many other types of wood. These qualities have inspired seafarers, gun manufacturers, and undertakers to use the wood to make boats, gunstocks, and coffins from the wood. Of course, many specimens of fine antique furniture are also made of this material. In fact, until mahogany came into fashion in the late 18th century, black walnut was the wood of choice of furniture makers. During World War I, the husks of the tree were used to produce a high-grade charcoal to filter gas masks. In the mid-20th century, various parts of the tree were used to make an insecticide and herbicide, the effectiveness of which was owing to the presence of juglone.

Juglone, chemically known as 5-hydroxy-alphanapthaquinone, is classified an allelochemical, meaning that it negatively affects the growth of certain neighboring plants by impairing enzymatic processes necessary for survival. This is why some gardeners consider black walnut to be a hindrance in terms of limiting options in landscaping. Regardless, juglone is potent stuff. It’s the reason that black walnut trees are rarely impacted by disease and explains why insects won’t even come into contact with the leaves.