What to Grow Under a Walnut Tree?


20150628Black walnuts (Juglans nigra), and, to a lesser degree, other species of walnut, produce a toxic substance called juglone from both their roots and leaves. Juglone is said to be allelopathic, that is to say, specifically toxic to other plants.

Walnuts use juglone as a defense mechanism: by eliminating competing plants, they can more easily dominate the sector and benefit from all the ressources: minerals, water, etc. Even their own nuts have trouble germinating in their root zone, ensuring the mother tree can grow without competition.

If you’re growing a walnut tree, or intend to grow one, don’t give up all hope of having a beautiful and productive garden at its base. There are still many plants that are juglone-resistant.

Here’s a list to get you started!

  • Astilbe (Astilbe spp.) zone 4
  • Bean (Phaseolus vulgaris) vegetable
  • Beet (Beta vulgaris) vegetable
  • Bellflower (Campanula spp) zones 3-7
  • Bergenia (Bergenia spp.) zone 3
  • Black raspberry (Rubus occidentalis) zone 4
  • Bleeding heart (Dicentra spp.) zone 3
  • Boston Ivy (Parthenocissus tricuspidata) zone 4b
  • Brunnera (Brunnera macrophylla) zone 3
  • Bugleweed (Ajuga reptans) zone 3
  • Burning bush (Euonymus alata) zone 5
  • China pink (Dianthus chinensis) annual or perennial (zone 4)
  • Chrysanthemum (Chrysanthemum x morifolium) zones 4-7
  • Cleome (Cleome hasslerana) annual
  • Climbing honeysuckle (Lonicera spp.) zone 3
  • Coleus (Plectranthus scutellarioides) annual
  • Columbine (Aquilegia spp.) zone 3
  • Coral Bells (Heuchera spp.) zone 3
  • Corn, maize (Zea mays) grain
  • Crocus (Crocus spp.) zone 3
  • Daffodil, jonquil (Narcissus spp.) zone 3
  • Daylily (Hemerocallis spp.) zone 3
  • Eastern hemlock (Tsuga canadensis) zone 4
  • Epimedium (Epimedium spp.) zone 3
  • Evening primrose (Oenothera spp) zone 4
  • February daphne (Daphne mezereum) zone 3
  • Flowering fern, royal fern (Osmunda spp.) zone 3
  • Forsythia (Forsythia spp.) zones 4-7
  • Four o’clock (Mirabilis jalapa) annual
  • Garden impatiens (Impatiens walleriana) annual
  • Garden phlox (Phlox paniculata) zone 3b
  • Goat’s beard (Aruncus dioicus) zone 3
  • Grape hyacinth (Muscari spp.) zone 3
  • Hardy geranium (Geranium spp.) zone 4
  • Hollyhock (Alcea rosea) zone 3
  • Horned pansy (Viola cornuta) zone 4
  • Hosta (Hosta spp.) zone 3
  • Hyacinth (Hyacinthus orientalis) zone 4
  • Iris (Iris spp.) zones 3-8
  • Japanese maple (Acer palmatum) zone 5b
  • Japanese pachysandra (Pachysandra terminalis) zone 4
  • Juniper (Juniperus spp.) zones 1-7
  • Lady’s mantle (Alchemilla mollis) zone 3
  • Lamb’s ear (Stachys byzantina) zone 3
  • Leopard’s bane (Doronicum spp.) zone 4
  • Ligularia (Ligularia spp.) zones 3-4
  • Lima bean (Phaseolus lunatus) vegetable
  • Lungwort (Pulmonaria spp.) zone 3
  • Male fern (Dryopteris filix-mas) zone 5
  • Meadowsweet, dropwort, queen-of-the-prairie (Filipendula spp.) zone 3
  • Monarda, bergamot (Monarda spp.) zone 3
  • Morning glory (Ipomoea nil) annual climber
  • Northern maidenhair fern (Adiantum pedatum) zone 3
  • Onion (Allium cepa) vegetable
  • Pansy (Viola x wittrockiana) annual
  • Parsnip (Pastinaca sativa) vegetable
  • Showy stonecrop (Hylotelephium spectabile, syn. Sedum spectabile) zone 3
  • Shrub rose (Rosa spp.) zones 3-7
  • Siberian squill (Scilla siberica) zone 2
  • Snowdrop (Galanthus spp.) zone 3
  • Solomon’s seal (Polygonatum spp.) zone 3
  • Spiderwort (Tradescantia x andersoniana) zone 4
  • Sweet woodruff (Galium odoratum) zone 3
  • Tiarella, foamflower (Tiarella spp.) zone 3
  • Toad lily (Tricyrtis spp.) zones 4-6
  • Tulip (Tulipa spp.) zone 4
  • Viburnum (Viburnum spp.) zones 2-8
  • Violet (Viola spp.) zones 2-8
  • Virginia creeper (Parthenocissus quinquefolia) zone 3
  • Wax begonia (Begonia x semperflorens-cultorum) annual

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