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:
Buxus spp. — I have many varieties — they all thrive!
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 I moved most of these elsewhere; occasionally one still pops up under the walnut
Hellebores – thrives
Hosta spp. — most do very well, the gold ones don’t do as well as the green/blue cultivars
Polygonatum biflorum ‘Variegatum’ – new, okay so far
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. Update: seem to do okay if it’s in a moist area.
Athyrium naponicum (Japanese Painted Fern) – thrives
Begonia grandis — planted late fall 2016 & thought they were toast but they came back strong!
Camellia — I remain determined to grow Camellia, despite earlier losses. Stay tuned.
Carex flaccosperma — thriving; in moist areas, it is spreading like crazy
Carex pensylvanica (Pennsylvania Spurge) — thrives!
Carpinus caroliniana — so far, so good. Mine doesn’t get v. good fall color, though.
Cercis canandensis — doing well at two years in
Chaenomeles speciosa ‘Scarlet Storm’ – planted in spring 2017 — did not do well this summer, will watch; March 2018 – top looks dead but coming back at the roots
Chamaecyparis pisifera ‘Filifera Aurea’ – pretty good; but mine might be just outside the BW root zone
Cotoneaster salicifolius ‘Repens’ (Willowleaf Cotoneaster) — does just fine
Deutzia gracilis ‘Chardonnay Pearls’ declined rapidly perhaps from lack of moisture?
Digitalis mertonensis (Strawberry Foxglove) — great first year, but petered out after; I think that’s normal for a foxglove. Can use as annual
Dryopteris marginalis (Leatherwood fern) — does well
Echinacea purpurea — thrives and seeds around
Eleutherococcus sieboldianus ‘Variegatus’ (Variegated Aralia) — thrives!
Euonymus americanus (Hearts a Burstin’)– thriving
Fargesia rufa ‘Green Panda’ (Green Panda Clumping Bamboo) — thrives!
Fothergilla major ‘Blue Shadow’ – very bummed that this died; might have been too dry
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) tragic — all three I planted died within 2 years. Too dry and cold? Soil not acid enough?
Ilex verticillata (Winterberry Holly) — doing great in a spot just outside the dripline
Imperata cylindrica (Japanese Bloodgrass) — pretty good
Iris germanica — does very well if there’s enough sun
Itea virginica — not good. Planted 3 of these 2 years ago and they are slowly dying back. They were in a dry spot, though. Very sad.
Hemerocallis (Daylily) — I have a few different cultivars that vary from excellent to pretty good. The wild orange one definitely thrives.
Hibiscus syriacus (Rose of Sharon) – wild ones pop up from seed; one day I might try one of the nice cultivated ones like ‘Bluebird’
Lindera benzoin (Spicebush) — volunteer; thriving
Magnolia virginiana (Sweetbay Magnolia) — not thriving, but hanging in there
Malus spp. (Ornamental Crabapple) — the one planted in my yard declined from lack of sun, I believe. It was planted long ago when there was likely more sun.
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.
Packera aurea — thrives and spreads, perhaps even too much
Phlox paniculata (Garden Phlox) — thrives!
Prunus laurocerasus ‘Schipkaensis’ — one died, other 3 okay so far. Watching these. Update winter 2018: oh no! A second one died!
Rohdea japonica (Sacred Lily) — thrives
Sarcococca hookeriana var. humilis (Sweetbox) — so-so. Better in moister areas.
Sedum — thrives where it gets enough sun. I have ‘Autumn Joy’ and a smaller unknown cultivar, maybe ‘Neon’?
Sedum ternatum — does pretty well; it’s cute; not very dense but mine planted in heavy shade
Solidago flexicaulis (Zigzag goldenrod) — thrives. This guy is literally at the foot of my BW
Spigilia marilandica (Indian Pink) — new in spring 2017, did great first year — high hopes!
Stylophorum diphyllum — thriving; this plant pops up all over but in a cute way
Symphorocarpus — not sure which species I have, but it does well.
Thuja occidentalis (Arborvitae) ‘Yellow Ribbon’ — doing great
Tradescantia virginiana (Spiderwort) — thrives
Tricyrtis hirsa (Toad lily) — thrives
Tsuga canadensis (Canadian Hemlock) not thriving, just surviving; soil not acid enough?
Viburnum x bodnantense ‘Pink Dawn’ died within a year
Viburnum x juddii — doing okay; just moved it right under drip line and will watch; seems susceptible to pests
Viburnum nudum — not thriving, just surviving
Plants that have died under the dripline: Camellia sasanqua ‘Yuletide’, Aucuba serratifolia, Pieris ‘Mountain Fire’