The Black Walnut tree (Juglans nigra) is an allelopathic plant. This means that it can suppresses the growth of many different types of plant. The Black Walnut releases a chemical into the soil called juglone which causes the poor growth or outright death of many plants planted under and around the tree. The area affected can reach a 50-60 foot radius around the tree and so meti mes even 80 feet. Luckily for those of you who inherit a black walnut tree with a new ho me there are many types of plants that are not susceptible to the juglone chemical so gardening can still be a joy. Here is a list of plants that have been observed growing under and near Black Walnut trees. As for grass Kentucky Bluegrass grows well under Black Walnuts.

Plants Tolerant of Black Walnuts
Trees
Autumn Olive Oleaceae spp. Honey Locust Gleditsia triacanthos
Black Haw Viburnum prunifolium Japanese Maple Acer palmatum
Beech Fagus sp. Lilac Syringa
Bigleaf Linden Tilia platyphyllas Nothern Red Oak Quercus rubrum
Black Cherry Prunus serotina Ohio Buckeye Aesculus glabra
Black Gum Nyssa sylvatica Papaw Asimina triloba
Black Locust Robinia pseudoacacia Quince Cydonia oblonga
Black Maple Acer nigra Red Cedar Juniperus virginiana
Black Oak Quercus ventutina Red Maple Acer rubrum
Box Elder Acer negundo Red Oak Quercus borealis
Callery Pear Pyrus calleryana Redbud Ceris canadensis
Canadian Hemlock Tsuga canadensis Sassafrass Sassafrass variifolium
Carolina Silverbell Halesia carolina Sugar Maple Acer saccharum
Catalpa Catalpa bigoniodes Sumac Rhus hirta
Flowering Dogwood Cornus florida Sweetgum Liquidamber styraciflua
Goldenrain tree Koelreuteria paniculata Sycamore Plantus occindentalis
Hackberry Celtis occidentalis Tree of Heaven Ailanthus glandulosa
Hawthorn Crataegus spp. Tulip Tree Liriodendron tulipifera
'Heritage' River Birch Betula nigra White Mulberry Morus alba
Hickory Caraya sp. White Oak Querus alba
Herbaceous Plants
Ajuga Ajuga reptans Leopard's Bane Doronicum sp.
Aster Aster spp. Lungwort Pulmonaria sp.
Astilbe Astilbe sp. Mayapple Podophyllum peltatum
Beebalm Monarda didyma Merrybells Uvularia grandiflora
Beebalm Monarda fistulosa Milkweed Asclepias syriaca
Bellflower Campanula latifolia Mustards Brasicca spp.
Bidens Bidens spp. Ox-eyed Daisy Chrysanthemum leucanthemum
Bloodroot Sanguinaria canadensis Phlox Phlox paniculata
Chicory Cichorium intybus Pinks Dianthus armeria
Chrysanthemum Chrysanthemum Primrose Primula x polyantha
Cinnamon Fern Osmunda cinnamomea Sedges Carex spp.
Coral Bells Heuchera x brizoides Sedum Sedum acre
Crested Wood Fern Dryopteris Sedum Sedum spectabile
Crocus Crocus spp. Shasta Daisy Leucanthemum
Daisy Flebane Erigeron annus Siberian Iris Iris sibirica
Daylily Hemerocalis sp. Solomon's Seal Polygonatum commutatum
Dutchman's Breeches Dicentra cucullaria Spiderwort Tradescantia virginiana
European Wild Ginger Asarum edropaeum Spring Beauty Claytonia virginica
Geranium Geranium sanguimeum Sundrops Oenothera fruticosa
Geranium Geramium robertianum Sweet Woodruff Galium odoratum
Hawkweed Hieraclum aurantiacum Tall Bellflower Campanula americana
Hollyhock Alcea rosea Trillium Trillium grandiflorum
Horsetail Equisetum arvense Trillium Trililium cernumm
Hosta Hosta marginata Violets Viola canadensis
Hosta Hosta fortunei h. lancifolia Violets Viola sororia
Hosta Hosta lancifolia Virginia Waterleaf Hydrophyllum virginianum
Hosta 'Glauca' Hosta fortunei Wild Ginger Asarum virginicum
Hosta 'Variegata' Hosta undulata Wild Senna Cassia marilandica
Iris, Siberian Iris sibirica Wild Sensitive Plant Cassia nictitans
Jack-in-the-Pulpit Arisaema triphyllum Windflower Anemone spp.
Jacob's-Ladder Polemonium reptans Yarrow Achillea millefolium
Lamb's Ear Stachys byzantina    
Shrubs
Alternate-Leaf Dogwood Cornus alternifolia Hibiscus Hibiscus
Arborvitae Thuja sp. Juniper Juniperus
Azalea, Exbury Hybrid Rhododendron Kerria Kerria japonica
Barberry Berberis canadensis Maple-Leaf Viburnum Viburnum acerfolium
Beauty Bush Kolkwitzia amabils Mock Orange Philadelphus sp.
Black Raspberry Rubus occidentalis Rose of sharon Hibiscus syriacus
Currant Ribes spp. Smooth Sumac Rhus glabra
Daphne Daphne Spicebush Lindera benzoin
Elderberry Sambucus canadensis St. John's Wort Hypericum prolificum
Euonymus, Winter Creeper Euonymus Viburnum Viburnum lantana
False Indigo Baptisia australis Wild Grape Vitis spp.
Forsythia spp. Forsythia Wild Rose Rosa spp.
Hazelnut Corylus Americana    
Annuals
Begonia Begonia
Calendula Calendula
Morning Glory Ipomoea
Pansy Viola
Zinnia Zinnia sp.
Vegetables
Squashes
Melons
Beans
Carrots
Corn
Fruit
Peach
Nectarine
Cherry
Plum
Bulbs
Crocus Crocus
Daffodil Narcissus
Glory-of-the-Snow Chionodoxa lucilliae
Grape Hyacinth Hyacinth oreintalis
Snowdrop Gulanthus
Spanish Blue Bell Endymion hispanica
Squill Scilla
Tulip Tulipa
Winter Aconite Eranthis
Vines
Clematis Clematis
Honeysuckle Lonicera tatarica
Virginia Creeper Parthenocissus quinquefolia
Bittersweet Celastrus scandens
Sweet Autumn Clematis Clematis ternifolia
Sweet Virgin's Bower Clematis virginiana