Juglone Tolerant Plants
Some landscape plants such as Juglans and various Carya species are allelopathic; produce a toxic substance that will suppress the growth of some species of plants within the underlying canopy area. The specific substance produced by Juglans nigra (Black Walnut) and related species is called hydrojuglone, which oxidizes into a toxic substance called juglone. This chemical is of concern when trees are encountered in the landscape, as it will limit what may be grown under or near them. Professionals are left with only two solutions to the problem, one being removal of the problem tree and the other, planting Juglone tolerant plants such as those listed below. Mature Juglans and Carya species present dramatic forms in the landscape and every effort should be made to retain healthy trees. Further reading is provided in the Ministry of Agriculture and Food information bulletin entitled Black Walnut Toxicity includedin this manual.
JUGLONE TOLERANT PLANTS
HERBACEOUS PERENNIALS
Ajuga reptans Bugleweed
Alcea rosea Hollyhock
Arisaema triphyllum Jack-in-the-Pulpit
Asarum canadense Wild Ginger
Astilbe X Garden Astilbe
Athyrium Lady Fern
Campanula latifolia Bellflower
Chrysanthemum sp. Garden Mums
Doronicum sp. Leopard’s Bane
Dryopteris cristata Shield Fern
Epimedium sp. Barrenwort
Galium odoratum Sweet Woodruff
Geranium sp. Garden Geraniums
Helianthus tuberosus Jerusalem Artichoke
Helleborus sp. Garden Hellebore
Hemerocallis sp. Daylily
Heuchera sp. Coral Bells
Hosta fortunei ‘Glauca’ Plantain Lily
Hosta lancifolia Plantain Lily
Hosta marginata Plantain Lily
Hosta undulata ‘Variegata’ Plantain Lily
Iris siberica Siberian Iris
Matteuccia struthiopteris Ostrich Fern
Mertensia virginica Virginia Bluebells
Monarda didyma Bee Balm
Myosotis sylvatica Garden-forget-me-not
Oenothera fruticosa Common Sundrops
Onoclea sensibilis Sensitive Fern
Osmunda cinnamonea Cinnamon Fern
Phlox sp. Summer Phlox
Poa sp. Blue Grass
Podophyllum peltatum Mayapple
Polemonium reptans Jacobs Ladder
Polygonatum commutatum Solomon’s Seal
Polystichum sp. Christmas Fern
Primula sp. Garden Primrose
Pulmonaria sp. Lungwort
Sanguinaria canadensis Bloodroot
Sedum sp. Sedum
Stachys sp. Lamb’s Ears
Tradescantia virginiana Spiderwort
Trillium sp. Trillium
Uvularia sp. Uvularia
Viola sp. Violets
Vinca minor Common Periwinkle
JUGLONE TOLERANT PLANTS
BULBS
Chionodoxa luciliae Glory of the Snow
Crocus sp. Garden Crocus
Endymion hispanicus Spanish Bluebell
Eranthis hyemalis Winter Aconite
Galanthus sp. Snowdrops
Hyacinthus sp. Hyacinthus
Muscari sp. Grape Hyacinth
Narcissus sp. Daffodils
Scilla siberica Siberian Squill
Tulipa sp. Tulips
JUGLONE TOLERANT PLANTS
TREES
Acer palmatum Japanese Maple
Carya sp. Hickories
Catalpa sp. Catalpa
Juniperus virginiana Red Cedar
Picea abies Norway Spruce
Quercus sp. Oaks
Syringa sp. Lilac
Tsuga canadensis Canada Hemlock
JUGLONE TOLERANT PLANTS
VINES AND SHRUBS
Clematis sp. Clematis
Daphne mezereum Daphne
Euonymus alatus Burning Bush
Forsythia sp. Forsythia
Hibiscus syriacus Rose of Sharon
Kolkwitzia amabilis Beauty Bush
Lonicera tatarica Tattarian Honeysuckle
Parthenocissus quinquefolia Virginia Creeper
Philadelphus sp. Mockorange
Rhododendron
‘Pinxterbloom’ Pinxterbloom Azalea
‘Gibraltar’ Gibraltar Azalea
‘Balzac’ Balzac Azalea
Rubus occidentalis Black Raspberry
Viburnum lantana Wayfaring Tree
JUGLONE TOLERANT PLANTS
ANNUALS
Begonia sp. Begonia
Calendula sp. Calendula
Ipomea sp. Morning Glory
Viola sp. Pansy
Note: Where a Genus is listed most species are also tolerant of Juglone, additionally; where a species is listed most cultivars of that specific species will be tolerant of Juglone.