The Black Walnut tree contains a substance that is toxic to many plants. This chemical, called juglone, is present in all parts of the tree and affects growing beneath and around the tree. The root systems and reach of juglone have been shown to extend 70-80' away from the trunk of the tree. This means a large portion or most of your yard to be affected by the tree.

Juglone damage appears as yellowing or browning of the leaves, stunted growth, or slow growth. Damaged caused by Black Walnuts and juglone cannot be reversed. The only solution is to select plants that can tolerate the chemical.

Some plants have been shown to exhibit a high tolerance to jugalone, while others have a very low success rate when grown near Black Walnuts. We have gathered information about plants that have shown a tolerance to juglone. Because each variety can vary, we do recommend doing a small planting at a time to test the plants ability to tolerate your yard's concentration of juglone.

Tolerant Trees

Acer palmatum :: Japanese Maple
Acer rubrum :: Red Maple
Acer saccharinum :: Sugar Maple
Amelanchier :: Serviceberry
Betula :: Birch
Catalpa :: Catalpa
Cercis :: Redbud
Cornus :: Dogwood
Crateaegus :: Hawthorn
Gleditsia :: Honeylocust
Halesia :: Silverbell
Liquidambar :: Sweetgum
Liriodendron :: Tulip Tree
Nyssa :: Black Gum
Platanus :: Sycamore/London Plane Tree
Quercus :: Oak
Thuja :: Arborvitae
Tsuga :: Hemlock
Ulmus americana :: American Elm

Tolerant Shrubs

Berberis :: Barberry
Euonymus :: Burning Bush
Forsythia :: Forsythia
Hamamelis :: Witchhazel
Hydrangea :: Hydrangea
Hypericum :: St. John's Wort
Kerria :: Japanese Kerria
Liqustrum :: Privet
Physocarpus :: Ninebark
Syringa :: Lilac
Viburnum carlesii :: Koean Spice or Cayuga Viburnum
Viburnum lantana :: Mohican Viburnum

Tolerant Perennials and Vines

Ajuga :: Bugleweed
Anemone :: Anemone
Aster :: Aster
Astilbe :: Astilbe
Clematis :: Clematis
Ferns :: All varieties
Gallium :: Sweet Woodruff
Geranium :: Hardy Geranium/Cranesbill
Heuchera :: Coral Bells
Hemerocallis :: Daylily
Liriope :: Lily Turf
Lobelia :: Cardinal Flower
Iris :: Siberian Iris
Leucanthemum :: Shasta Daisy
Lonicera :: Honeysuckle
Mondara :: Bee Balm
Polemonium :: Jacob's Ladder
Pulmonaria :: Lungwort
Rudbeckia :: Black-Eyed Susan
Sedum :: Stonecrop
Tradescantia :: Spiderwort
Verbascum :: Mullein
Veronica :: Speedwell
Viola :: Viola
Wisteria :: Wisteria