Black Walnut Can Influence the Plants Around It

Black Walnut produces juglone-related compounds, with the greatest concentrations occurring in its buds, nut hulls and roots. Small amounts released around living or decaying roots can inhibit certain sensitive plants.

Surprising takeaway: A Walnut tree can affect more than the shade directly beneath its branches. Susceptible plants may wilt within its root zone, while juglone-tolerant species continue growing nearby.