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Perennials & Grasses to try under
Black Walnut Trees

If you have a Black Walnut tree in your yard, you may have observed the difficulty in finding plants to thrive under their branches and in their root zone.

The root, bark and seeds of the Black Walnut (Juglans nigra) gives off a chemical, called juglone, which is toxic to many plants. In addition, the soil under a Black Walnut tends to be quite alkaline, compared to the soil outside of the tree’s root spread. (The soils in Southeastern Wisconsin tend to be naturally alkaline)

The following list was compiled from many sources. Although these perennials have exhibited a high tolerance to juglone, their appearance on this list does not imply 100% success.

If you would like to try perennials not on this list, experiment by planting a small number first. Observe the plants for at least a full growing season before adding additional plants. Yellowing or browning of leaves, stunted growth or a failure to grow, are all signs of Juglone damage.

Black Walnut Tolerant Plants

PERENNIALS

AJUGA
ALCEA
ANEMONE virginiana
ANTENNARIA dioica
ARISAEMA triphyllum
ASARUM europaeum
ASTER
ASTILBE
CAMPANULA carpatica
CHELONE
CLAYTONIA virginica
CONVALLARIA majalis
DICENTRA cucullaria
DICENTRA spectabilis
DORONICUM
ECHINACEA purpurea
ERIGERON speciosus
ERYTHRONIUM americanum
EUONYMUS fortunei
EUPATORIUM maculatum
EUPATORIUM purpureum
GALIUM odoratum
GERANIUM maculatum
GERANIUM sanguineum
GEUM species
HELENIUM autumnale
HELIANTHUS occidentalis
HEMEROCALLIS (Daylily)
HEUCHERA
HOSTA

HYDROPHYLLUM virginianum
IRIS Germanica
IRIS siberica
LEUCANTHEMUM
LILIUM michiganense
LILIUM superbum
LIRIOPE spicata
LOBELIA siphlitica
MONARDA species
NEPETA species
ORIGANUM laevigatum
Herrenhausen
PACKERA aurea
PAEONIA species
PENSTEMON species
*PENSTEMON digitalis
PEROVSKIA species
PHLOX species
PHYSOSTEGIA species
POTENTILLA species
PRIMULA species
PRUNELLA grandiflora
PYCNANTHEMUM
RATIBIDA pinnata
RUDBECKIA species
RUELLIA humilis
SALVIA species
SCABIOSA species
SEDUM species
SOLIDAGO species
SPIGELIA marilandica

FERNS

ATHYRIUM species
DRYOPTERIS species
ONOCLEA sensibilis
OSMUNDA cinnamomea
POLYSTICHUM acrostichoides

GRASSES

CALAMAGROSTIS
DESCHAMPSIA
FESTUCA
HAKONECHLOA
HYSTRIX

VINES

ARISTOLOCHIA durior
CELASTRUS scandens
CLEMATIS
LONICERA
PARTHENOCISSUS quin. Engelmanii

*Butterfly host plants