Yes, some locust trees have thorns, but it depends on the tree. The truth about locust tree thorns comes down to which tree you mean. Black locust grows small paired spines. Wild honey locust grows long branching thorns that look downright dangerous. Most honey locusts sold for yards today carry no thorns at all, since growers pick thornless types on purpose. You will not know which one you have until you look at the tree yourself.
"That thing will be nothing but thorns," my neighbor warned me over the fence the week I planted mine. He was picturing the wild honey locust down the road, all spikes and menace. But the Sunburst honey locust in my front yard has never pushed out one thorn. It is a named cultivar, bred to stay smooth, and the nursery tag said so in plain print.
The two thorn types look and behave in very different ways. Honey locust thorns are modified branches. They grow straight from the trunk and the big limbs, often in branching clusters, and a single one can reach several inches long. Black locust spines are a different beast. They are small and paired, sitting right at the base of each leaf where it meets the twig. You can snap them off with a thumb, while a honey locust thorn will fight back. Brush a bare arm on black locust and you feel a scratch. Lean on a honey locust trunk and you get stabbed.
Not sure which locust you have? Look at the leaves and the pods first. Honey locust leaves are fine and fern-like, and its pods grow long, flat, and twisted, sometimes a foot or more. Black locust leaves are rounder, and its pods are short and smooth. Check the bark too, since you can often spot old thorn scars on a honey locust trunk. Once you name the tree, the thorn pattern makes sense.
Age changes the story on locust tree thorns too. A young tree of either kind can be the spiniest it will ever be. The pattern then shifts as the wood matures and the crown fills in. The two trees do not follow the same path, though. Here is how black locust and honey locust thorns stack up side by side.
- Small paired spines sit at the base of each leaf, most under half an inch long.
- They cling to young twigs and green shoots, then fade as the bark thickens with age.
- This tree suckers hard, so fresh spiny shoots can pop up yards away from the trunk.
- Long branching thorns grow from the trunk and limbs, and many top three inches.
- Thorn output slows or stops in the upper crown as the tree gets older.
- About 60% of seedlings from thornless seed stay thornless too, per USDA Silvics.
For a yard, a patio, or anywhere bare feet go, buy a named thornless honey locust cultivar. Sunburst, Shademaster, and Skyline are proven picks with no thorns and no messy pods to rake. Get them from a nursery tag you trust. Ask the staff to confirm the cultivar name before you pay, so you know just what you are taking home. A cheap seedling grown from random seed can still surprise you with a mouthful of spines down the line.
Out in the wild, treat honey locust with real respect. The fallen thorns are stiff enough to punch through a boot sole or a mower tire, so rake them up before you work the soil. If a volunteer locust pops up along your fence line, pull it while it is young. Wear thick gloves when you gather the thorns, and check your tires after you mow near one. Locust tree thorns only get harder and sharper as the wood ages, and a mature trunk is no fun to clear.
Read the full article: Locust Tree: Honey vs Black Locust Guide
