Sep 18, 2018, 12:04
Both are in the Juglandaceae (Walnut) family. Like Juglans nigra (black walnut), Juglans cinerea (butternut) produce a substance called juglone in roots, fruit husks and leaves that is toxic to some plant species. This substance which is very toxic to certain other plants such as azaleas, rhododendrons, blueberries, peonies and solanaceous crops (tomatoes, peppers, potatoes). Most of the toxicity is limited to within the drip line of the tree, but the area of toxicity typically increases outward as the tree matures.