The roots, hulls and buds of black walnut trees contain juglone, a chemical that suppresses the ability of susceptible plants to produce energy for metabolic energy. Affected plants turn yellow, wilt and eventually die. Juglone persists in the soil for several years after black walnut roots are removed.
About this Author
Melody Lee worked as a newspaper reporter, copywriter and editor for 5 years. In addition, she has edited magazine articles and books. Lee holds a degree in landscape design and is a Florida master gardener. She has more than 25 years of gardening experience, which includes working at nurseries and greenhouses.