With most trees, it’s best to let fallen leaves remain where they lie, but you can further reduce the concentration of juglone in the soil around a black walnut tree by keeping the area clean.

While producing this substance benefits the black walnut tree by limiting competition, it harms other vegetation, causing yellowed, wilted leaves and ultimately death from being exposed to juglone.

This week, we meet Black walnut or Juglans nigra. Also known as American black walnut or eastern black walnut, this species has compound leaves with several pairs of leaflets along the individual leaf ...