Black Walnut, is a fast-growing Midwest native tree of bottomlands and open fields. Its beautiful, fine-grained wood is prized for woodworking and quality veneer. Nutmeats enjoyed by humans and wildlife. Juglone, a natural allelopathic chemical produced by walnut trees inhibit growth of nearby plants. Those particularly affected include tomatoes and related plants like eggplants, chiles, potatoes and petunias. In addition, some ornamental plants are also sensitive, such as potentillas, lilacs, columbines, lilies, and peonies. These plants should be grown 50 feet or more outside of the walnut tree's dripline.
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Valuable timber tree |
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Good nut producer |
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Can inhibit growth of nearby plants |
More About Juglans nigra:
The type of relationship between plants, like Black Walnut, in which one produces a substance which affects the growth of another is known as "allelopathy." In fact, Black Walnut is famous for root production of juglone, a chemical that is toxic to some nearby competitor plants. In a woodland setting, very few plants grow under the canopy of this species.
Aside from leaf spot, Black Walnut is virtually disease and pest free. When summer drought occurs, the response of this tree is to begin dropping leaves, in spite of its deep taproot system. The Black Walnut is not the best urban tree because it requires much clean-up from dropped leaflets, dead twigs, stain-laden whole fruits and debris from squirrel feeding.
