Black Walnut Tree Toxicity

The Black Walnut (juglans nigra) is a vigorous hardy tree for Western New York.Unfortunately, the black walnut’s roots, which may extend 50 feet or more from the trunk, do exude a natural herbicide known as juglone that prevents many plants from growing within their reach.

Tomatoes, potatoes, apples, pears, berries, and some landscape plants such as rhododendrons, azaleas, and lilacs may be killed or stunted if grown in close proximity to black walnut roots.