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:
Acer japonicum ‘Butterfly’ — I bought a very tiny specimen and planted it right in the middle of the lawn. Perhaps it was too exposed but it didn’t survive the winter 😦 Acer japonicum ‘Aconitifolium’ I am still grieving for this one. Bought it last summer, watered it diligently…it didn’t survive the winter, and this winter was mild. I am not sure why Japanese maples won’t grow in my backyard, but it breaks my heart.
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’ – thriving and spreading steadily
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. Update: Having luck with some Camellia japonica: they started as small specimens but are growing slowly. I also have a few C. sasanquas but they seem to struggle.
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. Update: as of spring 2020 this small tree is thriving & the fall color is improving as it grows.
Cercis canandensis — doing well at two years in. Update: the original plant was a tiny whip. About 4 years later (5?) it’s about 10 feet tall and wide and flowered beautifully this spring for the first time.
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 Update: total goner.
Chamaecyparis pisifera ‘Filifera Aurea’ – pretty good; but mine might be just outside the BW root zone
Cotoneaster salicifolius ‘Repens’ (Willowleaf Cotoneaster) — does just fine Update: I eventually pulled these out and replaced with boxwood. They didn’t die, but they looked straggly and I did not find them attractive after a few years.
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. But if it gets too much shade it is leggy and needs staking and the purple color is not as vibrant.
Eleutherococcus sieboldianus ‘Variegatus’ (Variegated Aralia) — thrives! The arching habit on this shrub is a double-edged sword. It can look kind of elegant, but it roots where it touches the ground, in addition to sending up suckers. The suckers are often plain green and not as graceful. All of this, plus the thorns, make this shrub a mixed bag.
Euonymus americanus (Hearts a Burstin’)– thriving
Fargesia rufa ‘Green Panda’ (Green Panda Clumping Bamboo) — thrives!
Forsythia spp. I have several of these and I appreciate the cheerful yellow flowers in spring but the rest of the year, meh.
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
Gladiolus spp. These looked great the first couple of summer but now they seem to have stopped flowering.
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. Update Spring 2020: still doing pretty well; it’s a little rangy because it gets quite a bit of shade, but it’s healthy enough, I think.
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
Narcissus spp. Excellent! I have several varieties: ‘Tete a Tete’, ‘February Gold’, ‘Mallee’ plus a few unknown ones…they all flower well if they get enough sun.
Osmanthus heterophyllus ‘Goshiki’ — My dog might have peed on it too much.
Packera aurea — thrives and spreads, perhaps even too much Update: BEWARE! This plant is taking over my yard!!!
Phlox paniculata (Garden Phlox) — thrives! BUT, it seeds around quite a bit and the seedlings tend to get powdery mildew, at least for me. Butterflies love these flowers, though, so they are wonderful from July-Sept.
Prunus laurocerasus ‘Schipkaensis’ — one died, other 3 okay so far. Watching these. Update winter 2018: oh no! A second one died! Update: a third died back a lot but is coming up from the roots. The fourth (and final) one is thriving. Weird!!
Rohdea japonica (Sacred Lily) — thrives
Sarcococca hookeriana var. humilis (Sweetbox) — so-so. Better in moister areas. Update: this is spreading more and looking better as the years go by. Patience is in order.
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. Update: it’s seeding around a lot. Not a problem yet but will watch.
Spigilia marilandica (Indian Pink) — new in spring 2017, did great first year — high hopes! Update spring 2020 — this plant seemed to disappear the next year, then returned in 2019. Definitely not spreading or vigorous.
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. Update: not thrilled with the weird spidery branches this shrub puts out at ground level as a way of spreading.
Thuja occidentalis (Arborvitae) ‘Yellow Ribbon’ — doing great
Tradescantia virginiana (Spiderwort) — thrives
Tricyrtis hirsa (Toad lily) — thrives. Update: another
quick spreader. Gotta watch it.
Tsuga canadensis (Canadian Hemlock) not thriving, just surviving; soil not acid enough? Update: both of the hemlocks did so poorly that I took them out. However, there was an established hemlock already on the property and that one continues to do well. It’s about 25′ tall.
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 Update spring 2020: I think it’s dead 😦
Viburnum nudum — not thriving, just surviving (The virburnums are breaking my heart)
Plants that have died under the dripline: Camellia sasanqua ‘Yuletide’, Aucuba serratifolia, Pieris ‘Mountain Fire’