Dwight Sipler wrote:

Juglone does not prevent all plants from growing near the walnut tree,
but some plants are inhibited. Look up "walnut wilt" on Google for a
list of susceptible plants.

In wild areas, plants that are not susceptible to juglone will
predominate around your walnut trees. However, if you try to introduce
other varieties you may run into trouble.

For example, tomatoes. When their roots touch the roots from the walnut tree
the plants wilt and die rather quickly.
Carl