What Will Grow Near a Black Walnut Tree?

Black Walnut trees are wonderful if you are a cabinet maker, eat the walnuts, or leave them as forage for wildlife, or use the husks to make a colorfast dye.  But if you are a gardener, they provide a challenge, to say the least.

A toxic chemical, juglone, diffuses from the roots into the soil, and is leached out of fallen bark, leaves, and fruit from Black Walnut trees.  This chemical inhibits the growth of certain plants.  (The closely related Butternut tree does the same, as well as some Hickory species.)  It would be wise to not use any part of the Black Walnut tree for mulch or in compost.  Also beware of leaves or nuts falling onto plants or the ground around them.

The toxic root zone from a mature tree occurs on average in a 50 to 60 foot radius from the trunk, but can be up to 80 feet.  The area affected extends outward each year as a tree enlarges.  Young trees two to eight feet high can have a root diameter twice the height of the top of the tree, with susceptible plants dead within the root zone and dying at the margins.  Evidence indicates that the toxic effect does not remain in the soil more than about one year after removal of a walnut tree.

Various studies have been done to determine what does and does not grow under or near Black Walnut trees.  One study showed that deciduous rhododendrons prospered, but evergreen cultures quickly died.  Also some tulip and narcissus cultivars thrived, others did not.  The results are listed below.

Plants Observed Growing Under or Near Black Walnut*

Trees

  • Japanese Maples, Acer palmatum and its cultivars
  • Southern Catalpa, Catalpa bignonioides
  • Eastern Redbud, Cercis canadensis
  • Canadian Hemlock, Tsuga canadensis
  • American Arborvitae, Thuja occidentalis
  • Shagbark Hickory, Carya ovata
  • Sugar Maple, Acer saccharum
  • Osage Orange, Maclura pomifera

Vines and Shrubs

  • Clematis ‘Red Cardinal’
  • February Daphne, Daphne mezereum
  • Euonymus species
  • Weeping Forsythia, Forsythia suspensa
  • Rose of Sharon, Hibiscus syriacus
  • Tartarian Honeysuckle, Lonicera tatarica, and most other Lonicera species
  • Virginia Creeper, Parthenocissus quinquefolia
  • ** Pinxterbloom, Rhododendron periclymenoides
  • **’Gibraltar’ and ‘Balzac’, Rhododendron Exbury hybrids
  • Multiflora Rose, Rosa multiflora
  • Black Raspberry, Rubus occidentalis
  • ** Koreanspice Viburnum, Viburnum carlesii, and most other Viburnum species
  • Silver Lace Vine, Polygonum aubertii

Annuals

  • Pot-marigold, Calendula officinalis ‘Nonstop’
  • Begonia, fibrous cultivars
  • Morning Glory, Ipomoea ‘Heavenly Blue’
  • Pansy Viola
  • Zinnia species

Vegetables

  • Squashes, Melons, Beans, Carrots, Corn

Fruit Trees

  • Peach, Nectarine, Cherry, Plum, Apple
  • Prunus species Pear-Pyrus species

Herbaceous Perennials

  • Bugleweed, Ajuga reptans
  • Hollyhock, Alcea rosea
  • American Wood Anemone, Anemone quinquefolia
  • Jack-in-the-Pulpit, Arisaema triphyllum
  • European Wild Ginger, Asarum europaeum
  • Astilbe species
  • Bellflower, Campanula latifolia
  • **Chrysanthemum species (some)
  • Glory-of-the-Snow, Chionodoxa luciliae
  • Spring Beauty, Claytonia virginica
  • Crocus species
  • Dutchman’s Breeches, Dicentra cucullaria
  • Leopard’s-Bane, Doronicum species
  • Crested Wood Fern, Dryopteris cristata
  • Spanish Bluebell, Endymion hispanicus
  • Winter Aconite, Eranthis hyemalis
  • Snowdrop, Galanthus nivalis
  • Sweet Woodruff, Galium odoratum
  • Herb Robert, Geranium robertianum
  • Cranesbill, Geranium sanguineum
  • Grasses (most) Gramineae family
  • Jerusalem Artichoke, Helianthus tuberosus
  • Common Daylily, Hemerocallis ‘Pluie de Feu’
  • Coral Bells, Heuchera x brizoides
  • Orange Hawkweed, Hieracium aurantiacum
  • Plantain-lily, Hosta fortunei ‘Glauca’
  • Hosta lancifolia
  • Hosta marginata
  • Hosta undulata ‘Variegata’
  • Common Hyacinth, Hyacinthus Orientalis ‘City of Haarlem’
  • Virginia Waterleaf, Hydrophyllum virginianum
  • Siberian Iris, Iris sibirica
  • Balm, Monarda didyma
  • Wild Bergamot, M. fistulosa
  • Grape Hyacinth, Muscari botryoides
  • Sweet Cicely, Myrrhis odorata ‘Yellow Cheerfulness,’ ‘Geranium,’ ‘Tete a Tete,’ ‘Sundial,’ and ‘February Gold’
  • Sundrops, Oenothera fruticosa
  • Senstitive Fern, Onoclea sensibilis
  • Cinnamon Fern, Osmunda cinnamomea
  • Peony, **Paeonia species (some)
  • Summer Phlox, Phlox paniculata
  • Mayapple, Podophyllum peltatum
  • Jacob’s-Ladder, Polemonium reptans
  • Great Solomon’s-Seal, Polygonatum commutatum
  • Polyanthus Primrose, Primula x polyantha
  • Lungwort, Pulmonaria species
  • Bloodroot, Sanguinaria canadensis
  • Siberian Squill, Scilla sibirica
  • Goldmoss Stonecrop, Sedum acre
  • Showy Sedum, Sedum spectabile
  • Lamb’s-Ear, Stachys byzantina
  • Spiderwort, Tradescantia virginiana
  • Nodding Trillium, Trillium cernuum
  • White Wake-Robin, Trillium grandiflorum
  • Tulipa Darwin ‘White Valcano’ and ‘Cum Laude,’ Parrot ‘Blue Parrot,’ Greigii ‘Toronto’
  • Big Merrybells, Uvularia grandiflora
  • Canada Violet, Viola canadensis
  • Horned Violet, Viola cornuta
  • Woolly Blue Violet, Viola sororia

*These are based upon observations and not from clinical tests.
**Cultivars of some species may do poorly.

Plants That Do Not Grow Within 50 Feet of Drip Line of Black Walnut

Herbaceous Perennials

  • Colorado Columbine, Aquilegia caerulea
  • Wild Columbine, Aquilegia canadensis
  • *Chrysanthemum Chrysanthumum species (some)
  • Baptisia australis
  • Hydrangea species
  • Lilies, Lilium species (particularly the Asian hybrids)
  • Alfalfa, Medicago sativa
  • Buttercup, Narcissus ‘John Evelyn,’ ‘Unsurpassable’ ‘King Alfred’ and ‘Ice Follies’
  • Peonies, *Paeonia species (some)

Trees

  • Silver Maple, Acer saccharinum
  • European Alder, Alnus glutinosa
  • White Birches, Betula species
  • Northern Hackberry, Celtis occidentalis
  • Norway Spruce, Picea abies
  • Mugo Pine, Pinus mugo
  • Red Pine, Pinus resinosa
  • Basswood, Tilia heterophylla

Shrubs

  • Red Chokeberry, Aronia arbutifolia
  • Hydrangea species
  • Mountain Laurels, Kalmia species
  • Privet, Ligustrum species
  • Amur Honeysuckle, Lonicera maackii
  • Brush Cinquefoil, Potentilla species
  • Rhododendrons and Azaleas, **Rhododendron species (most)
  • Blackberry, Rubus allegheniensis
  • Yew, Taxus species
  • Blueberry, Vaccinium corymbosum
  • *Viburnum plicatum tomentosum ‘Mariesii’

Annuals and Vegetables Transplants

  • Cabbage, Brassica oleracea capitata
  • Peppers, Capsicum species (some)
  • Tomatoes, Lycopersicon esculentum
  • Flowering Tobacco, Nicotiana alata
  • Petunia species and cultivars
  • Eggplant, Solanum melongena
  • Potato, Solanum tuberosum
  • double-flowered cole vegetables

*Cultivars of some species may survive but will do poorly. Soil type and pH may affect plant survivability.

Plant list is from the Ohio State University.

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3 thoughts on “What Will Grow Near a Black Walnut Tree?

    1. Thank you for your question! That is something I do not know about. As far as I know, no research has been done on that, since most figs are not hardy enough to grow where the majority of black walnuts grow. I have a fig tree in my backyard, Zone 5b, and it is within 100 feet of a black walnut, and has grown each year, though the spring temperatures keep it from starting growth until about July.

      The Kansas Gardener

  1. I have seen contradictory information regarding hydrangea and would love to know if the Tardiva variety is able to live under/near/around black walnuts. I have three small specimens that I grew from rooted twigs I got at a box store. They grew fine in pots and don’t seem to be suffering but haven’t grown much since I planted them in-ground last year. I live in zone 6 and we had a pretty mild winter last year. I’ve seen that ninebark is safe too, would you agree?

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