Can I Use Black Walnut Leaves for Compost?
By: Jessie Keith
“I have several black walnut trees in my yard. Would it be alright to use the leaves in the compost? Question from Raymond of Holt, Michigan
Answer: I would not recommend it. As you surely know, black walnut trees (Juglans nigra) excrete the toxin, juglone, which is deadly to quite a few ornamental plants. The toxin helps reduce competition, making black walnuts bad trees for small home landscapes. Who wants a deadly tree around? Still, black walnuts are beautiful and have edible nuts that feed wildlife, so they are best reserved for more wild areas or fencelines far from the home garden–unless you plant nothing but tolerant plants.
Juglone is largely excreted by the roots, but it is also found in lower quantities in the wood and leaves. The toxin can leach from leaves into compost in small quantities. That’s why you need to be careful about what you plant near a walnut tree and where you put walnut leaves, which are best taken to the woods, fenceline, or bagged for disposal.
Because you have a black walnut tree, it would be prudent to get to know plants that are resistant and sensitive to these trees. Please click here for a great list provided by the Morton Arboretum, a world-class tree resource.
Symptoms of Black Walnut Toxic Syndrome
Keep in mind that there is no cure once sensitive plants have been significantly impacted by juglone. Exposure signs include yellowing, wilt, stunted growth, and finally death. It may take plants months to die after exposure.
Black Gold Horticulturist
This site may contain content (including images and articles) as well as advice, opinions and statements presented by third parties. Sun Gro does not review these materials for accuracy or reliability and does not endorse the advice, opinions, or statements that may be contained in them. Sun Gro also does not review the materials to determine if they infringe the copyright or other rights of others. These materials are available only for informational purposes and are presented “as is” without warranty of any kind, express or implied, including without limitation warranties of merchantability, fitness for a particular purpose, and non-infringement. Reliance upon any such opinion, advice, statement or other information is at your own risk. In no event shall Sun Gro Horticulture Distribution, Inc. or any of its affiliates be liable to you for any inaccuracy, error, omission, fact, infringement and the like, resulting from your use of these materials, regardless of cause, or for any damages resulting there from.