Black Walnut Tolerant Plants
The black walnut tree (Juglans nigra) is a species known for its impressive stature and valuable wood. However, it also produces a natural compound called juglone, which can be toxic to certain plants. Juglone is present in all parts of the tree—leaves, bark, roots, and nuts—but its effects are most pronounced when the roots of the black walnut come into contact with the roots of susceptible plants.
Understanding Juglone Toxicity
Juglone toxicity often presents subtly at first, with affected plants showing symptoms like drooping outer growth (flagging), wilting leaves, and eventual decline. Unfortunately, once symptoms appear, the damage is irreversible. While some plants have a mild tolerance to juglone, they may still grow poorly, appearing stunted and failing to reach their full potential.
The roots of a mature black walnut tree can extend 50 to 60 feet from the trunk, creating a wide zone of influence. While some sources suggest juglone toxicity occurs only through root contact, others indicate it can also affect plants up to 20 feet beyond the root system’s edge due to juglone’s release into the soil. For this reason, selecting juglone-tolerant plants is crucial when gardening near black walnut trees.
Plants That Thrive Near Black Walnut Trees
Despite juglone’s toxicity, many plants are known to grow well in its vicinity. Below is a comprehensive list of juglone-tolerant species organized by category. If a plant you’re interested in isn’t listed, it doesn’t necessarily mean it won’t thrive; it may simply be untested in such conditions. Let us know if you’ve observed unlisted plants thriving near black walnuts—we’re always looking to expand and improve this guide!
Trees
- Japanese maple
- Red maple
- Sugar maple
- Ohio buckeye
- Serviceberry
- Pawpaw
- River birch
- American hornbeam
- Eastern redbud
- Fringe tree
- Pagoda dogwood
- Flowering dogwood
- Hawthorn
- Persimmon
- Forsythia
- Honey locust
- Walnut
- Juniper
- Sweetgum
- Tulip tree
- Magnolia
- Sycamore
- Ornamental pear
- Red oak
- Black locust
- Lilac
- Cedar
- Canadian hemlock
- Elm
Flowering Shrubs
- February daphne
- Burning bush
- Witch hazel
- Japanese kerria
- Beauty bush
- Honeysuckle (Lonicera spp.)
- Mock orange
- Ninebark
- Purple sand cherry
- Rose of Sharon
- Wild/smooth hydrangea
- Staghorn sumac
- Elderberry
- Viburnums (fragrant, arrowwood, and wayfaring tree)
- Adam’s needle (Yucca)
Fruits & Vegetables
- Cherry tree
- Nectarine tree
- Peach tree
- Plum tree
- Pear tree
- Black raspberry
- Grape
Vines
- Kiwi vine
- Dutchman’s pipe
- Bittersweet
- Clematis
- Honeysuckle vine
- Virginia creeper
- Wisteria
Perennials
- Bugleweed
- Hollyhock
- Jack-in-the-pulpit
- European wild ginger
- Garden astilbe
- Lady fern
- Bellflower
- Turtlehead
- Lily of the valley
- Bleeding heart
- Leopard’s bane
- Wood fern
- Coneflower
- Barrenwort
- Dogtooth violet
- Joe Pye weed
- Blue fescue
- Daylily
- Coral bells
- Perennial sunflower
- Plantain lily
- Bearded and Siberian iris
- Shasta daisy
- Lily-turf
- Lobelia
- Ostrich fern
- Virginia bluebells
- Bee balm
- Wild bergamot
- Sundrops
- Sensitive fern
- Cinnamon fern
- Japanese spurge
- Summer phlox
- Obedient plant
- Sweet woodruff
- Cranesbill
- Winter rose
- Spreading bamboo
- May apple
- Creeping Jacob’s ladder
- Great Solomon’s seal
- Solomon’s seal
- Christmas fern
- English primrose
- Lungwort
- Black-eyed Susan
- Bloodroot
- Creeping stonecrop
- Showy stonecrop
- Goldenrod
- Lamb’s ear
- Meadow-rue
- Spiderwort
- White clover
- Nodding trillium
- Great white trillium
- Globe flower
- Periwinkle
- Fern-leaved speedwell
Ornamental Grasses
- Bluestem
- Bulbous oat grass
- Mosquito grass
- Quaking grass
- Feather reed grass
- Northern sea oats
- Wheat grass
- Love grass
- Blue fescue
- Japanese forest grass
- Blue oat grass
- Sweet grass
- Japanese blood grass
- Silver/maiden grass
- Millet
- Switch grass
- Fountain grass
- Ribbon grass
- Northern pampas grass
- Moor grass
- Indian grass
- Cord grass
- Feather grass
Annuals
- Pot marigold
- Fibrous and tuberous begonia
- Impatiens
- Heavenly blue morning glory
- Pansy
- Zinnia
Bulbs
- Glory of the snow
- Crocus
- Grape hyacinth
- Daffodil
- Winter aconite
- Snowdrop
- Hyacinth
- Siberian squill
- Darwin and Gregii tulips
Plants That Struggle Near Black Walnut Trees
While many plants tolerate juglone, others are particularly sensitive and unlikely to thrive near black walnut trees. These include:
Trees
- Silver maple
- European alder
- White birches
- Japanese larch
- Saucer magnolia
- Norway spruce
- Mugo pine
- Red pine
- Scotch pine
- White pine
Shrubs
- Scarlet aronia
- Cotoneaster
- Hydrangea
- Mountain laurel
- Common privet
- Rhododendron
- Lilac
- Yew
- Doublefile viburnum
Perennials
- Wild columbine
- False indigo
- Lilies
- Peony
- Daffodil
Conclusion
Gardening near black walnut trees may pose challenges, but with careful planning and plant selection, it is possible to create a thriving landscape. When in doubt, consult this guide or reach out to us with your observations to help expand our knowledge of juglone-tolerant plants. Happy gardening!
