As you know, the lovely Black Walnut tree releases a chemical called juglone, which is toxic to many plants. If you’re like me, you’ve spent quite a bit of time seeking out lists on the internet that say which plants will or will not tolerate juglone. Unfortunately, these lists are often contradictory, and they only include a fraction of the available plants out there on the market. I have been gardening under several Black Walnut trees for quite awhile now, and I would like to share my own personal list of the plants that I have grown successfully under these beautiful trees.
Naturally this list is in no way comprehensive, but if you are an adventurous gardener and would like to try growing more than just a few plants near your Black Walnuts, perhaps it will give you some ideas. I will keep adding to these lists as I experiment with new plants! And I invite you to please tell me which plants YOU have been successful with under your Black Walnuts. Be sure to include your growing zone or location!
Plants Growing Right at the Base of Mary’s Black Walnut Trees:
Callicarpa americana — thrives!
Epimedium spp.– thrives! Love this plant.
Euonymus ‘Manhattan‘ — thrives! but susceptible to Euonymus leaf notcher insect
Euphorbia amygdaloides var. robbiae (Mrs. Robb’s Spurge), thrives
Plants Growing Beneath a Black Walnut Dripline:
Aesculus parviflora– thrives! I adore this guy!
Anemone japonica —thrives & spreads
Aruncus dioicus (Goatsbeard) might have survived with more moisture
Asimina triloba (Pawpaw) — thriving!
Astilbe spp.– too soon to say, I keep moving it around
Carex flaccosperma — thriving; in moist areas, it is spreading like crazy
Carex pensylvanica (Pennsylvania Spurge) — thrives!
Chamaecyparis pisifera ‘Filifera Aurea’
Cotoneaster salicifolius ‘Repens’ (Willowleaf Cotoneaster)
Deutzia gracilis ‘Chardonnay Pearls’
Digitalis mertonensis (Strawberry Foxglove)
Eleutherococcus sieboldianus ‘Variegatus’ (Variegated Aralia) — thrives!
Euonymus americanus — thriving
Fargesia rufa ‘Green Panda’ (Green Panda Clumping Bamboo) — thrives!
Fothergilla major ‘Blue Shadow’
Heuchera americana ‘Dale’s Strain’ — doing great even in dry soil
Heuchera ‘Caramel’ — died quickly, probably from frost heave, or it got too dry
Heuchera villosa ‘Autumn Bride’ — thrives where soil is moist
Ilex opaca ‘Greenleaf’ (American Holly)
Ilex verticillata (Winterberry Holly)
Hemerocallis fulga (Daylily)
Hibiscus syriacus (Rose of Sharon)
Lindera benzoin (Spicebush) — volunteer; thriving
Magnolia virginiana (Sweetbay Magnolia) — not thriving, just surviving
Malus spp. (Ornamental Crabapple)
Miscanthus sinsensis ‘Dixieland’ fizzled out within a couple years, but I’ve heard these variegated grasses do that
Osmanthus heterophyllus ‘Goshiki’ — My dog might have peed on it too much.
Phlox paniculata (Garden Phlox) — thrives!
Rohdea japonica (Sacred Lily)
Sarcococca hookeriana var. humilis (Sweetbox)
Stylophorum diphyllum — thriving; this plant pops up all over but in a cute way
Thuja occidentalis (Arborvitae)
Tradescantia virginiana (Spiderwort)
Tsuga canadensis (Canadian Hemlock) not thriving, just surviving; soil not acid enough?
Viburnum x bodnantense ‘Pink Dawn’ died within a year
Viburnum nudum — not thriving, just surviving
Plants that have died under the dripline: Camellia sasanqua ‘Yuletide’, Aucuba serratifolia, Pieris ‘Mountain Fire’