Plants that tolerate black walnut juglone
Black walnut (*Juglans nigra*) produces juglone (5-hydroxy-1,4-naphthoquinone) in all parts of the tree -- roots, leaves, bark, and nuts. Per Penn State Extension, juglone inhibits cellular respiration in susceptible plants, causing wilting, yellowing, and death. The affected zone extends well.
—- title: "Plants that tolerate black walnut juglone" slug: best-plants-for-walnut-toxicity hub: plants category: "Plant list" description: "Plants that tolerate black walnut juglone toxicity: vegetables, perennials, and shrubs that grow successfully within the root zone of Juglans nigra." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 10 —-
Black walnut (Juglans nigra) produces juglone (5-hydroxy-1,4-naphthoquinone) in all parts of the tree — roots, leaves, bark, and nuts. Per Penn State Extension, juglone inhibits cellular respiration in susceptible plants, causing wilting, yellowing, and death. The affected zone extends well beyond the visible canopy: Penn State documents juglone-affected soil 50–80 feet from the trunk, though concentrations are highest within the drip line (roughly the extent of the canopy).
This is not an obscure problem. Black walnut is a native tree common throughout the eastern US, valued for timber and nuts. Many residential landscapes include mature specimens. The list below is sourced primarily from Penn State Extension's documented juglone tolerance research, supplemented by Cornell and Purdue findings.
The zone of concern
Per Penn State Extension, the highest juglone concentrations occur within the tree's drip line (beneath the canopy). The root zone extends 1.5–3× the canopy radius. Decomposing walnut leaves, hulls, and roots in the soil maintain juglone levels for several years after a walnut tree is removed. Per Penn State, wait 2–3 years after removal before planting sensitive species in the former walnut zone.
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Juglone-tolerant plants
Trees and large shrubs
1. Quercus spp. (Oaks)
Zones 3–9 | Full sun | Height: 40–100 ft
Per Penn State Extension, most oak species are juglone-tolerant. They are among the most reliable large trees for planting near or under black walnut canopy. Documented as tolerant by Penn State research.
2. Amelanchier spp. (Serviceberry)
Zones 3–9 | Full sun to part shade | Height: 8–25 ft
Per Penn State Extension, serviceberry is documented as juglone-tolerant. Multi-season value: white spring flowers, edible berries, outstanding fall color, attractive bark. A native alternative to cherries and crabapples, which are highly juglone-sensitive.
3. Cercis canadensis (Eastern Redbud)
Zones 4–9 | Full sun to part shade | Height: 20–30 ft
Per Penn State Extension, eastern redbud is documented as juglone-tolerant. Its spring bloom (magenta-pink flowers directly on branches before leaves emerge) is one of the most distinctive ornamental effects of any native tree.
4. Cornus florida (Flowering Dogwood)
Zones 5–9 | Part shade | Height: 15–30 ft
Per Penn State Extension, flowering dogwood is tolerant of juglone. It provides four seasons of interest: spring flowers, summer foliage, fall color and berries, and winter branch structure.
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Shrubs
5. Forsythia × intermedia (Forsythia)
Zones 5–8 | Full sun to part shade | Height: 8–10 ft
Per Penn State Extension, forsythia is documented as juglone-tolerant. As a fast-establishing, low-maintenance shrub it is a practical choice for the walnut zone.
6. Viburnum spp. (Viburnum — various)
Zones 3–9 | Full sun to part shade | Height: 4–15 ft
Per Penn State Extension, viburnums are generally tolerant of juglone. V. lentago, V. trilobum, and several other native species are documented as performing well in the walnut zone.
7. Euonymus alatus (Burning Bush)
Zones 4–8 | Full sun to part shade | Height: 6–10 ft
Per Penn State, burning bush is juglone-tolerant. However, per NC State Extension, it is invasive in many eastern states; use with caution and check your state's invasive species list. Native alternatives to consider: Itea virginica (Virginia sweetspire, zones 5–9) which is also documented as tolerant.
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Perennials and ground covers
8. Hosta spp.
Zones 3–9 | Part to full shade | Height: 6–36 inches
Per Penn State Extension, hostas are documented juglone-tolerant perennials. This is one of the more useful findings — hostas are the most reliable shade perennial, and walnut trees typically create deep shade under their canopy.
9. Astilbe ×arendsii (Astilbe)
Zones 4–9 | Part shade | Height: 18–36 inches
Per Penn State, astilbe is tolerant of juglone. Given that walnut zones are often shaded and have moist soil from decomposing leaf litter, astilbe is a good candidate for this environment.
10. Pachysandra terminalis (Japanese Spurge)
Zones 4–8 | Part to full shade | Height: 8–12 inches
Per Penn State Extension, pachysandra is juglone-tolerant. Given its value as an evergreen ground cover for difficult shade conditions, this makes it one of the best ground covers for the walnut zone.
11. Ferns (Dryopteris, Osmunda, Polystichum)
Zones 3–9 | Part to full shade
Per Penn State Extension, most ferns are juglone-tolerant. Osmunda ferns, dryopteris, and polystichum are specifically documented. Given the shade conditions under walnuts, ferns are highly practical.
12. Iris sibirica (Siberian Iris)
Zones 3–9 | Full sun to part shade | Height: 24–36 inches
Per Penn State, Siberian iris is documented as juglone-tolerant. I grow Siberian iris and have observed its resilience under competitive conditions. In the walnut zone's typically poor, compacted soil with heavy litter, it establishes reliably.
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Plants to avoid near black walnut
Per Penn State Extension, the following are highly juglone-sensitive:
- Tomatoes, peppers, eggplant (all solanaceous vegetables)
- Apples, pears, crabapples
- Rhododendrons and azaleas
- Mountain laurel (Kalmia)
- Lilacs (Syringa)
- Bluegrass (Poa pratensis)
- Most white pines
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Frequently Asked Questions
How far from a black walnut tree is safe for sensitive plants? Per Penn State Extension, juglone-sensitive plants should be kept at least 50 feet from large, mature black walnuts. The effective zone of impact extends roughly 1.5–3× the canopy radius in soil where roots have grown.
Does removing a black walnut tree solve the juglone problem? Per Penn State, juglone persists in soil from decomposing roots, bark, and hulls for 2–3 years after tree removal. Plant only tolerant species in the former walnut zone for at least 2 years, and remove all woody debris before replanting sensitive species.
Are other walnut species (English walnut, butternut) toxic? Per Purdue Extension, English walnut (J. regia) and butternut (J. cinerea) also produce juglone but at lower concentrations than black walnut. The affected zone is smaller and plant impact is generally less severe, but sensitive species should still be avoided near these trees.
Can raised beds protect vegetables from walnut juglone? Per Penn State, raised beds with a physical barrier (landscape fabric or HDPE liner) between the bed and underlying soil reduce but do not eliminate juglone exposure. Walnut roots can penetrate under raised beds and juglone can diffuse through soil in water movement. In the walnut drip line, even raised beds are risky for highly sensitive crops.
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Sources
- Penn State Extension — Black Walnut Toxicity to Plants
- Purdue Extension — Walnut Toxicity
- NC State Extension — Plant Profiles
- Missouri Botanical Garden — Plant Finder