Black Walnut
Juglans nigra
Last reviewed: June 2026
Black Walnut (Juglans nigra) is a native deciduous tree found across eastern and central United States. It blooms in May and June, supporting bees and beetles as pollinators.
Black Walnut is toxic to dogs.
Listed as toxic by the ASPCA Animal Poison Control Center (opens in new tab) (last reviewed 2026-05-21). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435and your veterinarian's emergency line.
Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.
Black Walnut is listed as toxic to grazing livestock (cattle, sheep, and goats) at a slight level by the USDA PLANTS Database (opens in new tab). This is a livestock indicator and is separate from pet toxicity.
Light
part shade
Water
medium
Size
300"–600" H × 300"–600" W
Bloom
May, Jun
Native to
AL, AR, CT, DE and 29 more states
Pollinators
bees, beetles
Browse plants for this ecoregion
Black walnut is a large native shade tree that can reach 25-50 feet tall with an equally wide canopy. It produces edible nuts in fall and has distinctive compound leaves that turn yellow in autumn. The tree is allelopathic, meaning it releases chemicals that can inhibit the growth of many other plants nearby.
Growing Black Walnut
Grow Black Walnut in part shade and medium water. Mature plants reach 300 to 600 inches tall and spread 300 to 600 inches wide. Expect high maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Black Walnut takes more care to keep looking intentional in a front yard. Maintenance level: high. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Extremely large size inappropriate for most residential lots
- Drops messy nuts and leaves requiring constant cleanup
- Allelopathic properties can damage nearby ornamental plants
Wildlife value
Host plant for luna moth, viceroy butterfly, banded tiger moth.
Black walnut supports bees and beetles during its spring bloom period. The nuts provide food for squirrels, chipmunks, and other wildlife throughout fall and winter.
Common questions
- Where is Black Walnut native to?
- Black Walnut is native to much of the eastern and central United States, from southern New England west to Nebraska and south to northern Florida and eastern Texas.
- When does Black Walnut bloom?
- Black Walnut typically blooms in May and June, producing small greenish flowers before the leaves fully emerge.
- What pollinators visit Black Walnut?
- Black Walnut flowers attract bees and beetles, though the tree is primarily wind-pollinated.
- What growing conditions does Black Walnut prefer?
- Black Walnut tolerates a range of light conditions from full sun to partial shade and adapts to various moisture levels, though it grows best in deep, well-drained soils.
- Is Black Walnut toxic to dogs?
- Yes. Black Walnut is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Black Walnut toxic to cats?
- Black Walnut is not on the ASPCA Animal Poison Control Center toxic plant list for cats (aspca.org).
- Is Black Walnut toxic to livestock?
- Black Walnut is listed as toxic to grazing livestock such as cattle, sheep, and goats (slight severity) by the USDA PLANTS Database. This is separate from pet (dog and cat) toxicity.
- Is Black Walnut HOA-friendly?
- Black Walnut takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Pollinator Patch flags toxic plants like Black Walnut and shows pet-safe natives for your ecoregion instead.
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