If you have a Juglans nigra growing anywhere on your property, or if your neighbor’s J. nigra overhangs your property, I am pleased to welcome you to The Black Walnut Society!
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:
Epimedium spp.
Euonymus ‘Manhattan‘
Euphorbia amygdaloides var. robbiae (Mrs. Robb’s Spurge),
Hosta spp.
Plants that have died at the base of the tree — Heuchera ‘Caramel’ (maybe it got too dry)
Plants Growing Beneath a Black Walnut Dripline:
Allium spp.
Aruncus dioicus (Goatsbeard)
Asimina triloba (Pawpaw)
Astilbe spp.
Callicarpa americana (American Beautyberry)
Carex pensylvanica (Pennsylvania Spurge)
Chamaecyparis pisifera ‘Filifera Aurea’
Cotoneaster salicifolius ‘Repens’ (Willowleaf Cotoneaster)
Deutzia gracilis ‘Chardonnay Pearls’
Digitalis mertonensis (Strawberry Foxglove)
Eleutherococcus sieboldianus ‘Variegatus’ (Variegated Aralia)
Fargesia rufa ‘Green Panda’ (Green Panda Clumping Bamboo)
Forsythia spp.
Fothergilla major ‘Blue Shadow’
Heuchera americana ‘Dale’s Strain’
Gladiolus spp.
Ilex opaca ‘Greenleaf’ (American Holly)
Ilex verticillata (Winterberry Holly)
Iris germanica
Hemerocallis fulga (Daylily)
Hibiscus syriacus (Rose of Sharon)
Lindera benzoin (Spicebush)
Magnolia virginiana (Sweetbay Magnolia)
Malus spp. (Ornamental Crabapple)
Miscanthus sinsensis ’Dixieland’
Narcissus spp.
Osmanthus heterophyllus ‘Goshiki’
Phlox paniculata (Garden Phlox)
Rohdea japonica (Sacred Lily)
Sarcococca hookeriana var. humilis (Sweetbox)
Thuja occidentalis (Arborvitae)
Tradescantia virginiana (Spiderwort)
Tsuga canadensis (Canadian Hemlock)
Viburnum x bodnantense ‘Pink Dawn’
Plants that have died under the dripline: Camellia sasanqua ‘Yuletide’, Aucuba serratifolia, Pieris ‘Mountain Fire’
The large black walnut in the far corner of my yard has shown no effect, good or bad, on a sweep of variegated pachysandra, Pathenocissus quinqefolia on twenty feet of chain link, dwarf spruce, arborvitae, Joe-Pye weed, and Penissetum ‘Hameln.’ Daylilies don’t mind either.
Awesome. Thank you Mark!
Does anyone know if Bamboo will grow under black walnut, or if black walnut toxicity will control running bamboo growth?
I have Fargesia ‘Green Panda’ growing happily right under one of my black walnuts. That is a clumping bamboo. I have a feeling the juglone wouldn’t even make a running bamboo blink.
I have also had success with daffodils directly under my black walnut in my yard.
Yes, of course! I have daffodils growing all over the place as well. Thanks, Diana!
I’ve found that Itea (‘Little Henry’ Sweetspire) seem to do fine. It’s not been 10 years but I’m witnessing it working as we speak (on the dripline…. farther is better).
Thank you for your trial of plants around and under black walnuts! My garden of veggies and flowers is surrounded by these trees! I have ringed the bases with stella deoras (sp.?) and longafollia hostas, both doing fine. In the garden my day lilies,iris,cone flowers,beans,broccoli,carrots,radish,cabbage,kolrobi,sqush,gords,watermellon,zinia, and onions all do well. There are 2 old walnut stumps in the garden area besides the ones surruonding it. I now have 6 raised beds in the garden of cukes,lettuce,asparagas,herbs,peppers,eggplant, and cone flowers all doing well. Have rhubarb over one of the stumps.
When I filled the beds, I used composted leaves and of course included walnut leaves. So far the eggplant is ok. The tomatoes, of course, don’t do well. They have a garden to themselves at the end of my wild weed flower garden.
Would love to harvest the very mature walnut trees, but husband says no and want him more than garden- so far!
Question-how long does the juglone stay in the soil?
Trina, thanks so much for adding your plant list to my Black Walnut page! I am honestly surprised you are having success with so many vegetables in the vicinity of these trees. That is great though! Your question about how long julone stays in the soil is a good one, and I have to say I have no idea. I would imagine that once a tree is cut down and is no longer conducting photosynthesis it would not be able to produce any more juglone and that the dying roots just sort of shrivel and die out. This is the opinion of a liberal arts major, mind you, so take with many grains of salt.
Mary — I have ten acres of Black Walnut trees, which have grown up over the twenty years we have lived here. My husband and I have left this wild, for the birds and “critters”: lots of golden rod, pines, grasses of all sorts, and Russian Olives (invasive) seem to thrive. We also have one acre of English gardens (cottage flowers), and an extensive vegetable garden, down hill from all those BW’s. We have two “yard” BW’s which my husband will not let me touch. I have my strawberry and asparagus beds (raised) directly under one, and both are doing fine. Also peas and leeks seem to do well. Apple trees (duh!) have died, and apricots as well. I’m hoping to landscape native and edible shrubs in a large patch smack dab between (and under) these two, and really appreciate all the info given here. Oh, in researching the whole question of toxicity, I’ve come across many articles that say the juglone poison persists for years after the trees are cut down…
Thanks so much for all this info, Louise! I’m suprised at all the edibles you’ve been successful with beneath your BWs….that’s encouraging!
Thanks for a great and informative site. Alas some ‘real’ information from fellow gardeners. So much on the internet to discern through concerning ‘Juglone tolerance’.
I planted 21 ilex close to the drip of 5 HUGE walnuts today. 3 boys and 18 girls. Most people referance the shade… not if they are grown on the north side. I have lots of south facing sun on these trees which allows me to plant ‘in front of them’. I realize that my ilex can be grown in shade, but I also have what is called a ‘Mill Race’. It occasionally floods and becomes what it was intended for. I call it my double jeapordy area. WATER AND WALNUTS! I’ve also planted Cornus ‘Midwinter Fire’ here and Molinia ‘Skyracer’. En masse. Plan on planting lots of Solidago ‘Fireworks’ too.
I have some design experience and wanted something different!!!
Thank you for the heads up on the Fargesia… did not know it was tolerant either! This entertains my thought in planting some ‘Sasa Vetchii’ as a groundcover. This would be OUTSTANDING beneath my Ilex:)
Wow, you’ve got some serious walnuts! What kind of ilex did you plant? I’ve got 4 opacas growing under my walnuts and they’re pretty happy, shade and all. I love your idea of planting the Cornus and Molinia en masse….bet that’s gooooorgeous.
I planted ilex verticillata ‘Red Sprite’ and their companion male ‘Jim Dandy’. As you know they are deciduous and commonly referred to as Winterberry holly. ‘Red Sprite’ grows to just 3-5′. “Stooling” or the pruning of the cornus will keep it in bounds and produce spectacular color on new stems.
Yes, I am excited to see what it looks like with the first snow. Oooooh, did I say SNOW? Eeeeek, something to look forward too:)
We bought this house 2 years ago. We have almost an acre and love to garden. What a shock to find we have these awful trees to deal with having never heard of this before. Why would people want to create such an environmental impact when there are so many wonderful trees to chose from? This year we had to have a 30 to 40 ft. blue spruce cut down, every year it had less green branches. Last year the university extension service thought the tree needed water. Now my guess is how close it was to the walnut tree, I just pray that our blue spruce on our property line does not suffer the same fate. I am trying to be positive but I could just cry. The only thing good is the wisteria growing up into the walnut tree right in front of the house. Funny thing is that is the only walnut on our land the back fence has five self seeded trees growing on the
other side and the side property line all down our 300 ft. drive has mature walnuts. It seems like we just have to rely on the help of sites like yours to find the encouragement we need to build a beautiful garden without a lot of plants we have loved. Coming from California to Michigan was already enough of a challenge, now this!
Hi Janice- I wanted to reply to your comment because, in Kansas, I have so many clients who consistently lose Blue Spruce trees. Blue spruce (many but not all varieties) are picky about water (want just enough not too much- 1″ every 7-10 days) and soil. I’d use a gater bag (look it up!) if you aren’t already, to deliver the correct amount of water to the root zone only. As well, if your soil is compactable clay soil, be advised that spruces just don’t like it! While there are lots of nutrients therein, they are hard to access. Fertilize in the spring (an evergreen or acid fertilizer like Espoma Holly Tone) and add compost to the soil around the tree- this breaks up the clay soil (assuming this is what you have. If not, ignore me!). Also keep in mind that encroaching tree canopy (from whatever source) will cause a lot less light, therefore less growth, etc. in your spruce. If your needles start to turn pink= usually too much water. If your tree is weakened and suddenly starts to lose needles, look at aphids and spider mites. They attack spruce heavily and love an already compromised victim…. Hope your tree makes it!
Janice….
Did the extension check for bag worms on the tree? They can be a huge problem on blue spruce. They will exfoliate the needles. Some years they are worse than others.
Also… as for the environmental factor…. squirels will surely take those nuts and bury them everywhere! And once a seedling walnut emerges, it is very hard to get rid of. It simply cannot be cut off, they resprout. The walnut has a very long taproot.
Mary:
You already listed Lindera which seems to LOVE black walnut…Redbud is also perfectly happy with these wonderful native trees…
Donna
I have a 5 foot and a 3 foot dbh black walnut growing in the yard. I live in the Hudson Valley of NY. The larger BW has about a 120 foot crown, so you can see there is room for a great diversity of plants. Daffodil, scylla, snowdrop, winter aconite, bleeding heart, Canada mayflower, angelica, wild strawberry, garlic mustard, sugar maple, american elm, eastern juniper, redbud and white pine grow fine. Native yellow jewelweed (touch-me-not) is quite robust. The grass sod is usually thin and susceptible to being torn by mowing or foot traffic, although the grass is nice and green. Earthworms (Lumbricus terrestris) are abundant, which could contribute to this effect. I have seen the earthworms reduce a huge pile of BW leaves to crumbly soil in a year’s time. Moles come into the yard periodically but tend to tunnel in the areas not under the BW trees. There is one plant I can say does not tolerate the black walnuts: rhododendron languishes and dies.
I’m a biologist. I would like to find an easy way to test for juglone in soil. Judging by its chemical structure, it looks suspiciously durable. But I have no idea. Perhaps a simple test could be to try raising fast-growing seedlings of known susceptibilty in soil where juglone is suspected. A good test for compostability of juglone might be to get a bunch of BW leaves in a mesh bag and leave in the compost pile for a year–then use a seedling test for residual toxicity. Perhaps try to allow earthworms into the mesh bags, since they might harbor bacteria that successfuly degrade juglone.
Thanks so much for this post, Tim. I do love to hear what other people grow under BWs, and if you learn something useful with the juglone experiment, please do let me know! You are right about Rhodies languishing in the presence of juglone….mountain laurel, I hear, is also a goner with BWS.
Mary,
My pleasure! I will definitely let you know what I find out, with regards to composting juglone. You know, it’s interesting that I have two white pines under the walnuts and these are listed everyhere I’ve seen as sensitive. It may be that certain factors can ameliorate juglone toxicity. I have neutral pH soil (calcareous) and not particularly well-drained. I can’t think of exactly how this would affect the toxicity, however–except that most biological processes are sensitive to pH. Also, the white pines are close to a large grove of other white pines, from which they could derive some support through root grafting (common in white pine) and/or a shared mycorrhizal fungal network.
There are also just a few autumn blooming crocuses under the BWs, which I see others have had trouble growing. Go figure! Best of luck with the growing season.
Tim
I have a butternut (white walnut?) but some kind of worm destroys all the nuts. Is there some kind of trap I can buy? Or some other solution other than spraying a chemical? The tree is huge, so big it straddles two yards, so I can’t pick the nuts, but need to wait for them to fall.
Any advice would be greatly appreciated.
Regrettably, I have no advice for you on this one. Sorry. I might try calling your local extension agency, or maybe even a reputable arborist? Good luck!
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zone 6/7 southern new york (mainland)
some volunteers doing very well amongst the walnuts…
viola sororia (common violet)
Polygonum virginianum (Virginia knot weed)
Geum canadense (white avens)
Parthenocissus quinquefolia (virginia creeper)
Menispermum canadense (common moon seed)
have planted some bare root sambucus (elderberry). seems to be holding on.
i like to encourage native volunteers – trying to keep the dreaded garlic mustard at bay. For this reason i tend to like more “assertive” plants.
and…. i AM juglone tolerant!
Many thanks! Your approach is very wise!
Thank you so much for this! I have a ginormous (scientific term for “about 30-40 foot tall”) black walnut in the corner of my very small yard, and just last year it finally managed to kill off a lovely dogwood tree in its dripline. I am in zone 6, and I’ve had good luck with Asiatic lilies, blackberries, and raspberries, as well as the daffodils and Rose of Sharon mentioned above (though my Rose of Sharon has remained very small, about 4 feet tall at best).
Oh no, I am bummed to hear about the dogwood, since I recently planted two diff. Cornus species near my BWs. Thanks for your other suggestions!
We have a beautiful thriving dogwood (cornus florida) under a black walnut. From everything I’ve read, any species of dogwood should be compatible with black walnut. However, dogwood trees only live to be about 20 or 30 years old and are susceptible to various fungal diseases. So, I would suspect some other culprit for killing the dogwood.
Thanks for the comment. I have also read that walnut and dogwood are compatible. One other culprit with a struggling dogwood might be improper soil. I believe that most dogwoods enjoy slightly acidic soil. I’ve planted many acid loving plants (camellias, pieris, etc.) in my backyard that have slowly died, and I’ve come to the conclusion my soil is to blame rather than my walnut trees, though it could be a combination of both.
I have not read all comments regarding the type of dogwood being discussed. My lists say no to forbid anonymous, silky dogwood
Sorry to say I think an incomplete email went out when I dropped my phone. As I missed what the actual dogwood is being discussed I will only ask has anyone planted Dogwood -Venus. I just returned from the nursery and am anxious to add this lovely tree to my grounds but it would be an expensive mistake if it did not live. Thanks for your comments. Janice
Oh, those Venus dogwoods are gorgeous. I believe they are a hybrid between three different species, so I am unsure about their juglone tolerance. I had thought that all Cornus were juglone tolerant. I had not read that about silky dogwood.
Thanks for the support group.
My garden is outside the drip line of a giant black walnut, but still very much impacted by the root system and squirrels burying the nuts in my beds. I live in zone 6b and get a range of sun exposure.
Plants I have had luck with:
Sage
lavender
oregano
spider wort
holly hock
fennel
seedum (ground cover and upright)
cone flower
mums
hostas
astilbe
bleeding heart
Plants I had to dig out:
hydrangea (climbing and oak leaf)
azaleas
coral bells (both orange leaf and dark purple)
I put in some new “experiments” this spring that I am interested to see if anyone else has had good luck with:
Corydalis
hellebores
clematis
aster
balloon astra
shasta daisy
chives
basil
Thanks,
Rachel
Thanks so much for these lists, Rachel! I, too, have had to dig out some of the plants you mention. The most heart-breaking was the oak leaf hydrangea, possibly my favorite shrub. I tried it twice.
I have also struggled with heucheras, although I have some H. villosa that are thriving — I have both the cultivar ‘Autumn Bride’ which is glorious, and I’ve also just planted several straight H. villosa species.
I recently planted hellebores right at the base of one of my BW’s and they are thriving!
Also I have been meaning to mention pn my blog that last year I planted a bottlebrush buckeye under the BW drip line and it has tripled in size in one year. I love it!
Hi Rachel,
Just wondering if anyone has tried planting a Carolina Jessamine ‘Margarita’ vine near a black walnut… have scoured the Internet and haven’t found a hint in either direction.
Thanks!
Bridget
Hi Bridget,
Sorry, I haven’t seen anything about Carolina jessamine either. My motto when it comes to planting under black walnuts is “when in doubt, try it out” — unless it’s a really expensive plant!
wow!!! what a wealth of information!!! we live in the north georgia mountains, and we have at least 8 hahahaha *ginormous* black walnuts that form a beautiful canopy of shade in the backyard, and a small one in the front. honeysuckle, wild roses, violets, grapes, and blackberries all seem to be doing fine in the shade under and around the trees…..and of course the grass (i have no idea what kind….just the wild stuff that mother nature planted) grows like crazy!!! we have 3 apple trees on the opposite side of yard not near the BW and a small apple (think i threw a core out there years ago!!
) growing under a canopy of old….50+? oaks……
we recently tilled up a section of land south and uphill of the closest BW, planted watermelon, cantaloupe, beets, squash, onions, lettuce, spinach, peas, beans, and corn…..everything is growing like crazy!!! the neighbor who helped us till up the land told us we had *good dirt*
i had already *started* a garden in pots…..tomatoes and peppers mostly…..then i read that BW was not conducive to their health, so i guess i did that right without even knowing it!!! thanks for all the info!!!!
Hi there!
From what I’ve read, there’s a difference between what can grow directly under a black walnut and what can grow near but away from the drip line. For me, there are other complications so it’s uncertain whether the problem is juglone or water competition when things die near the dripline. I have a flowering dogwood and a Norway maple growing near the black walnut, all near the top of a slope. The maple in particular sucks a lot of water, so plants on top of the slope have a harder time. I lost a winterberry two years ago after planting just along the black walnut dripline, but it was also planted near the top of the slope. It died almost immediately but the two winterberries planted lower on the slope are thriving two years later. I think it may have been the heat and lack of water that killed it. Honestly, not many plants do extremely well near the base or under the dripline of any tree on our property, except for the undesirable invasives such as Japanese honeysuckle, multiflora rose, oriental bittersweet, and Japanese Stilt Grass. Virginia creeper, poison ivy, Bearded Iris and peonies also seem to survive anywhere.
Aster should do fine near a black walnut. Mine is thriving about 15 feet from the black walnut trunk. Also, I have native gooseberry growing happily near the aster. As you said, bleeding heart does fine, I have mayapple, Ostrich Fern, clethra, daphne and some European Consort Currant. Two of the four currants died and one of the three Ostrich ferns, but they were planted at the very top of the slope. The two currants that died were very close to the dogwood. Foamflower does fine near the black walnut, but not as well near the Norway maple. Native and European geranium, all kinds of phlox, Jacob’s Ladder, gray, red and yellow twig dogwood, smartweed, jack-in-the-pulpit, Maple Leaf Viburnum, Running Serviceberry, native honeysuckle, pokeweed, trumpet vine, any kind of native cherry tree, sassafras, hornbeam, hop hornbeam, tulip tree, red maple, mulberry, black or red elderberry, daffodils, wild violets/pansies, poison ivy and other kinds of rhus species including fragrant sumac and low gro fragrant sumac, native black raspberry, Dutchman’s pipe vine, strawberries, rue, Thai basil, Maypop, aspen, ash, partridgeberry, Montauk daisy, fig trees, redbud, and black cohosh, wild grape vine, are all growing happily near my black walnut tree. All kinds of wild sedge and blue-eyed grass, Virginia rose, red oak, pin oak, spicebush, black chokeberry, witch hazel and Japanese maple are all very happy near the black walnut. Japanese pachysandra is too happy near the black walnut, so I’m going to have to start ripping it out. All the invasives I mentioned before, Japanese Stilt Grass, multiflora rose, Japanese honeysuckle, oriental bittersweet and Garlic Mustard, are also too annoyingly happy.
I planted ligularia and cardinal flower under the black walnut today. According to online lists they are supposed to do fine so we’ll see.
From what I’ve read, almost anything in the honeysuckle family (and you’d be surprised how many plants are in this family), the buttercup family, the native euonymus family, and the sumac family can survive near black walnuts. Nothing in the rhododendron family can, and this includes rhodies, azaleas, blueberries, lingonberries, cranberries, wintergreen, heaths and heathers, bog rosemary, Japanese andromeda and bearberry.
I’ve also read that plants in the mulberry family, which includes fig, can create a buffer around the black walnut root system reducing the effects of juglone. Their roots fix nitrogen in the soil. So, I planted a small non-native mulberry to see what would happen. A native red mulberry would grow too large for the space. It’s happy, but I’m hoping in the long run it will help the Southern highbush blueberry shrubs planted 15 feet away continue to thrive.
Bridget,
Thanks so much for this thoughtful and comprehensive account of your experiences with BW! I am especially encouraged to see that daphne has been successful for you, since that is something I have always wanted to plant.
Mary