Planting for Screening Near Black Walnut
I have black walnut trees along my lot lines. What other plants & bushes will grow near these trees? I need to plant more coverage along the lot line.
Many gardeners struggle with this problem and I am continually asked for recommendations. As you know, all parts of the black walnut tree including the roots, fruits and leaves contain juglone. This is toxic to many plants. When susceptible plants come in contact with the juglone the leaves yellow and wilt. The plants may be stunted or eventually die.
Some plants like bluegrass are not sensitive while others like petunia are. Several shrubs including forsythia, most viburnums, rose of Sharon, wild rose, arborvitae, red cedar (Juniperus virginiana) and hemlock tolerate the black walnuts and would help provide some screening along your lot line.
Perennial flowers such as bee balm, Shasta daisy, most ornamental grasses, ferns, astilbe, wild ginger, Solomon's seal, Siberian iris, Virginia bluebells, some peonies, phlox and some daylilies could be used for seasonal color and texture.
Unfortunately there is not a complete list of all plants and their susceptibility or resistance to this substance. Take a look at Purdue University’s Black Walnut Toxicity bulletin for more complete listings of Black walnut susceptible and resistant plants.
If a plant you are interested in trying is not listed, as resistant or susceptible, you may want to experiment. Plant one or two under the black walnut tree’s canopy where the concentration of juglone is the greatest. If they survive you may want to use more of them to dress up your juglone zone. Whatever black walnut resistant plants you select, be sure they can tolerate the light, soil and growing conditions in the area and will have plenty of space to reach their full size.