B Is for Black Walnut Trees

The black walnut tree (Juglans nigra) is not usually grown in the home landscape but does have its benefits. On my homestead of about 40 acres, we have an expansive stand of woods which include several black walnut trees. They are massive and beautiful trees. We have collected nuts several times but more often than not, we simply appreciate its beauty.


The tree is long-lived and can last up to 200 years. Because of its size, it can make a wonderful shade tree. The problem with using it in this capacity is the nuts. In the fall, around October, the nuts, contained inside greenish hulls, fall from the tree once the hulls turn black. They are often plentiful and a nuisance to clean up. The hulls, when opened, can stain your skin.

Another problem with black walnut trees is that a chemical contained in the roots, trunk, leaves and nut husks can inhibit the growth of tomatoes, potatoes, blackberry, grape, lilac, hydrangea, chrysanthemum, paper birch, red (Norway) pine, Scotch pine, hackberry, basswood, apple, and other plants grown too close to a walnut tree. This effect remains long after a walnut tree has been removed. If you want the tree for its shade or bright yellow autumn display, plant it where it won’t impact other plants.

The nuts which are primarily used in ice cream, candy and baking are difficult to extract. The black walnut tree is a valued lumber tree because of the hardness of its wood. This hardness extends to the nut. Many people resort to spreading the nuts on the driveway and rolling over them with a car to crack the shells. I have actually tried this and it pretty effective.

Give careful consideration to the addition of a black walnut to your landscape. It is definitely a beautiful addition but not one without drawbacks.