deciduous tree
Black Locust: pruning, storm risk and removal
Robinia pseudoacacia. Also called False acacia, Yellow locust.
Plain-English notes for homeowners, plus field notes for tree crews. General guidance only: for one specific tree, have a local insured pro look at it.
Black Locust at a glance
| Height | 40-70 ft |
|---|---|
| Spread | 20-35 ft |
| Growth rate | Fast |
| USDA zones | 3-8 |
| Lifespan | typically 60-100 years |
| Type | Deciduous |
| Native range | Native to the Appalachian and Ozark regions of the eastern United States. It has been widely planted and is now considered invasive in parts of the country and in other continents. |
| Roots | Shallow and wide. It sends up many root suckers and can form thickets. It fixes nitrogen and grows well in poor, dry soils. |
| Wood | Very hard, heavy and rot-resistant. Long used for fence posts and outdoor structures. It is excellent firewood that gives high heat and burns slow, but it is hard to split and dulls chains. |
| Storm risk | mediumThe wood itself is very strong, but the branches are brittle and the crown is often irregular with weak forks. Limbs break in wind and ice. |
Typical ranges, not guarantees. Soil, water, space and care change how a tree grows. Storm risk is our general rating for the species, not an inspection.
For homeowners
Caring for a black locust
Best time to prune
Prune in late summer to early fall or in the dormant season. Remove dead wood and fix weak forks while the tree is young. Wear thick gloves and eye protection.
Avoid pruning
Avoid heavy cutting, which tends to trigger a flush of water sprouts and root suckers. Avoid working without eye protection, because of thorns.
More on timing: when to prune trees.
- Do not eat the bark, leaves or seeds. They are toxic, and the pods can attract curious children and pets.
- Suckers can pop up across the lawn. Mow them repeatedly to wear them down.
- Do not plant it near property lines if neighbors may not want a thicket. It is invasive in some areas.
- Look for sawdust or holes in the trunk. This can be locust borer damage.
Safety first
Do not climb a tree or use a chainsaw on storm-loaded or broken wood. If a tree or limb is touching power lines, stay away and call the utility. If someone is in danger, call 911. For anything big, hire a local insured pro: read how to hire a tree service and is my tree dangerous?
Lirevon does not do tree work. Find local pros on Google Maps and read their reviews, then get two or three written quotes.
For tree crews
Field notes: working on black locust
- 1Wear eye protection and heavy gloves. Thorns can puncture gloves, boots and rope bags.
- 2Wood is very hard. Expect fast chain wear and slow splitting.
- 3Plan for stump and sucker treatment. Regrowth is common after cutting.
- 4Cut logs make long-lasting posts, rails and firewood, so they are worth keeping.
Removal notes
Expect suckers after removal. Stump treatment by a licensed pro is often needed. Young shoots and twigs have sharp paired thorns. The bark, leaves and seeds are toxic if eaten. A common pest, the locust borer, tunnels into trunks and weakens stressed trees.
Wood
Very hard, heavy and rot-resistant. Long used for fence posts and outdoor structures. It is excellent firewood that gives high heat and burns slow, but it is hard to split and dulls chains.
Pricing this job? Try the tree job estimator. Follow your own safety plan and crew training on every job.
Common problems for black locust
Pests and diseases to watch for. Each link explains signs and what to do.
Trees often mistaken for it
Check the leaves, bark and shape before you decide how to prune or treat.
Where black locust grows
Native range: Native to the Appalachian and Ozark regions of the eastern United States. It has been widely planted and is now considered invasive in parts of the country and in other continents.
Common in these US regions. Tap one to see other trees there.
Free tools for this tree
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Black Locust: common questions
Is black locust poisonous?
Parts of the tree, including the bark, leaves and seeds, are toxic if eaten. The flowers are used in cooking in some places, but you should not eat any part without expert advice. Keep pets, horses and children away from the seeds and bark.
Why does black locust keep coming back after I cut it?
It spreads by root suckers and resprouts from stumps. Cutting alone usually triggers more growth. A licensed pro can advise on stump treatment, and repeat mowing helps.
Is black locust good firewood?
It is among the best. It gives high heat and burns long, but the wood is hard to split and should be seasoned for a year or more.
Does black locust have thorns?
Yes. Young stems and branches usually have a pair of sharp thorns at each leaf joint. Thorns are less common on older trunk wood. Some cultivars have fewer thorns.
Is black locust invasive?
In many places it spreads aggressively, especially into open land and along roadsides. It is native to a smaller area in the East. Check your state's invasive plant list.
How can I tell black locust from honeylocust?
Black locust has leaves with oval leaflets, white pea-like flowers in spring and short flat brown seed pods. Honeylocust has smaller, narrower leaflets, long twisted pods and often large branched thorns on the trunk.
More trees in the same regions
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