Black Walnut Trees
The roots of Black Walnut produce a substance known as juglone. Plants adversely affected by being grown near black walnut trees exhibit symptoms such as foliar yellowing, wilting and eventually death.
The toxic zone from a mature tree occurs on average in a 50-60 foot radius from the trunk.
Not all plants are sensitive to juglone. Plants grown by Great Garden Plants that have been observed growing under or near Black Walnut include:
Ferns: Dryopteris, Osmunda