Black Walnut Toxicity

Plants near black walnut trees show stunting and poor growth from juglone toxicity. Site plants away from walnuts. You are most likely to notice symptoms during periods of active growth, particularly when moisture levels favor pathogen development. Early recognition is your best advantage: the sooner you identify the problem, the more effective your management options will be.

Remove affected material as you find it and clean up any fallen debris where black walnut toxicity spores can overwinter. Improve air circulation around susceptible plants through selective pruning. Avoid overhead irrigation during vulnerable growth periods. If the problem is persistent, your local Extension office can recommend current fungicide or bactericide options for your specific situation.