How to Use Black Walnuts As a Natural Insecticide


Many people and small mammals consider black walnuts a delicious treat, but creatures of the insect world have a different take on the matter. The black walnut tree produces a strong-smelling, pungent substance called juglone, which is a natural insect repellent. You can take advantage of this strong scent and use the juglone-rich leaves and/or branches around your house as a natural repellent. But you'll need to be mindful of where you use the leaves and branches, because juglone can be harmful to nearby plants.

Step 1

Pull a few handfuls of leaves from your black walnut tree.

Step 2

Cut the leaves into ¼-to-½-inch pieces with scissors and put them in a measuring cup. Continue to collect and cut up leaves until you have approximately one quart, or four cups, of shredded leaves.

Step 3

Sprinkle the leaf cuttings around the perimeter of your house relatively close to the foundation without touching the structure itself.

Step 4

Allow the leaves to remain undisturbed for three weeks.

Step 5

Collect the used leaves after three weeks and replace with new cuttings, following steps one through four. Repeat the process every three weeks for maximum effectiveness.

Tips and Warnings

  • Avoid using black walnut leaves or branches anywhere near plants that are juglone-intolerant.

Things You'll Need

  • Gloves
  • Black walnut leaves
  • Scissors
  • Measuring cup
  • Bowl
  • Branches, if desired


  • "The Organic Gardener's Handbook of Natural Insect and Disease Control"; Barbara W. Ellis, Fern Marshall Bradley, Helen Atthowe; 1996

Who Can Help

  • A listing of juglone tolerant plants
Keywords: using black walnut as an insecticide, how to use black walnuts as a natural insecticide, black walnut uses

About this Author

Margaret Telsch-Williams is a freelance, fiction, and poetry writer from the Blue Ridge mountains. When not writing articles for Demand Studios, she works for as a contributor and podcast co-host.