CHRISTENSEN'S PLANT CENTER BLACK WALNUT “DO’S AND DON’TS” Black Walnut (Juglans nigra) produces a toxin, juglone, which can suppress or kill surrounding vegetation. The level of juglone in the soil is highest under the drip-line of the tree, and by 50-60 feet away is significantly less. Extremely susceptible plants have been injured as far as 80 feet away. Other trees which produce juglone are, in the order of concentration, English walnut (J. regia), Butternut (J. cineraria), Hickory (Carya ovata), and Pecan (C. illinoinesis).
We have compiled this list of plants with known susceptibility to juglone, as well as plants that have been listed as being resistant, however, no guarantee may be made. We have omitted some plants that are not recommended for use in land- scaping.
PLANTS SENSITIVE TO BLACK WALNUT TOXICITY CONIFERS & TREES
Acer saccharinum Silver Maple Syringa spp. Lilac Amelanchier canadensis Serviceberry Vaccinium spp. Blueberry Betula nigra River Birch Viburnum dentatum Arrowwood Viburnum Carpinus caroliniana American Hornbeam Viburnum opulus European Cranberrybush Celtis occidentalis Hackberry Viburnum plicatum Doublefile Viburnum Chionanthus virginica Fringetree Viburnum sieboldii Siebold Viburnum Halesia carolina Halesia Hamelis virginiana Witch Hazel HERBACEOUS Iles opaca American Holly Ilex verticillata Michigan Holly Baptisia australis False Indigo Larix laempferi Japanese Larch Aquilegia canadensis Wild Columbine Liquidambar sryraciflua Sweetgum Lilium Garden Lily Magnolia soulangiana Saucer Magnolia Paeonia Peony Malus spp. Crabapple, Apple Tulipa Tulip Pinus resinosa Red Pine Pinus strobus Eastern White Pine Pinus sylvestris Scotch Pine Picea abies Norway Spruce Quercus coccinea Scarlet Oak Quercus imbricaria Shingle Oak Thuja occidentalis Arborvitae Tilia americana Basswood
SHRUBS
Aronia arbutifolia Red Chokeberry Ceanothus americanus New Jersy Tea Cornus amomum Silky Dogwood Hydrangea spp. Hydrangea Kalmia latifolia Mountain Laurel Ligustrum spp. Privet Lonicedra maackii Amur Honeysuckle Physocarpus opulifolius Ninebark Pinus mugo Mugo Pine Potentilla fruiticosa Shrubby Cinquefoil Prunus tomentosa Nanking Cherry Prunus subhirtella ‘Pendula’ Weeping Higan Cherry Pyrcantha spp. Firethorn Rhododendron spp. Rhododendron / Azalea
6282 Gotfredson Rd. l Plymouth, Michigan 48170-5073 l (734) 454-1400 CHRISTENSEN'S PLANT CENTER BLACK WALNUT “DO’S AND DON’TS”
PLANTS TOLERANT OF BLACK WALNUT TOXICITY
CONIFERS & TREES HERBACEOUS & FERNS
Acer palmatum and cvs. Japanese Maple Achillea millefolium Common Yarrow Acer rubrum Red Maple Anemone spp. Thimbleweed Acer saccharum Sugar maple Antennaria spp. Pussytoes Aescuslus glabra Ohio Buckeye Arisaemea triphyllum Jack-in-the-pulpit Asimina triloba Pawpaw Asarum virginicum Wild Ginger Catalpa bignoides Common Catalpa Aster spp, Aster Cercis canadensis Eastern Redbud Campanula americana Tall Bellflower Cornus florida Flowering Dogwood Carex spp. Sedge Crataegus spp. Hawthorn Claytonia spp. Spring Beauty Fagus grandifolia American Beech Crocus spp. Crocus Gleditsia triacathos Honeylocust Dennstaedtia punctiloba Hay-scented Fern Juniperus virginiana Red Cedar Dryopteris marginalis Leather Wood Fern Liriodendron tulipifera Tuliptree Erigeron annuus Daisy Fleabane Nyssa sylvatica Black Gum Erigeron philadelphicus Common Fleabane Platanus occidentalis Sycamore Eupatorium coelestinum Mist Flower Quercus alba White Oak Eupatorium purpureum Joe-pye Weed Quercus borealis Red Oak Galium spp. Sweetwoodruff Quercus velutina Black Oak Geranium spp. Wild Geranium Sassafras allaidum Sassafrass Geum spp. Avens Tsuga canadensis Canadian Hemlock Helenium spp. Sneezeweed Ulmus americana American Elm Helianthus spp. Sunflower Hemerocallis spp. Daylily SHRUBS, VINES, & GROUNDCOVERS Impatiens Jewelweed Leucanthemum maximum Shasta Daisy Berberis canadensis American Barberry Leucanthemum vulgare Ox-eye Daisy Celastrus scandens American Bittersweet Lobelia spicata Spliked Lobelia Cornus alternifolia Pagoda Dogwood Malva rotundifolia Common Mallow Corylus americana American Hazelnut Monarda fistulosa Wild Bergamot Hydrangea arborescens Wild Hydrangea Monarda punctata Horsemint Hypericum prolificum Shrubby St. John's Wort Muscar spp. Grape Hyacinth Pachysandra spp. Pachysandra Oenothera spp. Evening Primrose Parthenocissus quinquefolia Virgina Creeper Onoclea sensibilis Sensitive Fern Rhus glabra Smooth Sumac Osmunda cinnamomea Cinnamon Fern Rhus typhina Staghorn Sumac Podophyllum peltatum Mayapple Ribes spp. Currant Polystichum acrostichoides Christmans Fern Rosa spp. Wild Rose Potentilla canadensis Common Cinquefoil Rubus occidentalis Black Raspberry Rudbeckia hirta Brown-eyed Susan Viburnum acerifolium Maple-leaved Viburnum Scilla siberica Siberian Squill Viburnum prunifolium Black Haw Viburnum Smilacena racemosa False Solomon's Seal Solidago spp. Goldenrod Trillium spp. Trillium
This list was compiled from many reputable sources and represents the best information we have at this time. However, we make no guarantee as to the suitability of these recommendations as they pertain to your situation.
6282 Gotfredson Rd. l Plymouth, Michigan 48170-5073 l (734) 454-1400