Gardening Under a Black Walnut Tree
Part of the fun or for some the frustration of gardening is overcoming challenges and one big challenge for many gardeners is planting under a black walnut tree. All parts of this tree contain a toxic substance called juglone. One solution for gardeners is to grow juglone tolerant plants.
Some gardeners have the added challenge of shade. In this case you may want to include several varieties of coral bells for their interesting shaped and colored foliage. The variegated leaves of hosta and lungwort also help brighten the shade. For height you may want to include variegated Solomon's seal. Daring gardeners may decide to try their luck with Canadian ginger. Try using only a few plants to see if it will tolerate the juglone. Adding golden moneywort provides a nice contrast to the ginger.
A bit more information: Minimize your frustration by growing susceptible plants at least 50 feet away from your black walnut tree. The further you move away from the tree the lesser the concentration of the toxic juglone. Or create a juglone-free raised bed. Cover the soil and line the sides of the raised bed with water permeable weed barrier fabric. The fabric can help slow or prevent the invasion of black walnut roots into the raised bed garden. Cover the barrier as you fill the bed with fresh topsoil free of juglone. And if you decide to remove the tree, be patient. The juglone remains in the soil until the roots, nuts and leaves totally decompose.