Black Walnut Trees And Juglone Toxicity

Why some plants won’t grow under Black Walnut Trees.

Ideas for replacing a walnut tree with plants that are resistant to Juglone toxicity.

If you’ve ever removed a Black Walnut tree from your yard and have found that very few plants will grow in its place or the ones that do grow grow very poorly, the problem is generally due to a chemical that Walnut trees produce called Juglone.

Even if you’ve removed the tree completely and it has been gone for years, you may still find that plants still have a hard time growing. Some folks find than even if they replace the top soil several inches deep, the new plants still show signs of Juglone toxicity. The problem here is that until any remaining roots have completely decomposed, there will still be traces of the chemical in the soil.

The solution to getting plants to grow in the effected bare area in your yard may be to use plants that are resistant to Juglone toxicity. Many annuals will do well as will these in the following list.

Juglone Resistant Plants

The following perennials, shrubs, and bulbs are generally resistant to Juglone toxicity.

Shrubs

  • Rose Of Sharon Hibiscus
  • Japanese Maple
  • Spirea

Bulbe

  • Crocus
  • Tulips
  • Daffodil

Perennials

  • Astilbe
  • Columbine
  • Coral Bells
  • Daylily
  • Spiderwort
  • Yarrow

If you have Black Walnut trees or plan to plant them in your landscaping, keep in mind that roots will generally go to or slightly past the drip zone of the trees. You shouldn’t plan to have any gardens, lawn, or landscaping plants in the area. Root barriers like driveways or sidewalks may help as separators as long as leaves, nuts, and other tree debris aren’t allowed to settle in desirable growing areas.

More Resources and Juglone Resistant Plant Ideas

Black Walnut Toxicity

Black Walnut Toxicity to Plants, Humans and Horses

About Juglone From Wikipedia

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