Best Bets: Plants for Particular Uses
These plants are recommended by Extension Master Gardeners for use near black walnut trees. A plant tolerant of black walnut means that it may survive under the canopy of a black walnut tree without being adversely affected by the toxic chemicals that the tree produces.
Though grown primarily for its wood and nuts, black walnuts are often found growing on landscape sites where they serve primarily as shade trees. When certain other landscape plants are planted near or under this shade tree they tend to yellow, wilt, and die. This decline occurs because the walnut tree produces a non-toxic, colorless, chemical called hydrojuglone. Hydrojuglone is found in leaves, stems, fruit hulls, inner bark and roots. When exposed to air or soil compounds, hydrojuglone is oxidized into the allelochemical juglone, which is highly toxic.Appleton, Bonnie Lee, et. al. 2009. The Walnut Tree: Allelopathic Effects and Tolerant Plants. Virginia Cooperative Extension.