The same fast growth that makes locust trees useful for shade and firewood also makes them weedy. Root suckers and seedlings pop up well beyond where you planted the tree. The main locust tree problems are aggressive suckering, invasive spread, and toxic parts on black locust. Add borer damage, brittle limbs that snap in storms, and thorns on wild trees. You get a tough, fast tree, but it fights to stay in bounds.
Spread is the biggest headache for most yards. Black locust invasive growth shows up on noxious-weed lists in several states, from the Midwest to parts of the West. The tree sends up new shoots from its roots, so one trunk can turn into a dense thicket over a few years. Cut it down and the problem gets worse, because damage triggers even more suckers. Seeds carry the tree into fields and woodland edges where you never wanted it.
Pests hit black locust harder than almost any tree in its range. The USDA Silvics Manual makes the point plain. Black locust takes more insect and disease damage than almost any tree in the East. The locust borer is the main culprit. Its larvae tunnel through the trunk and branches, and those tunnels open the door for heart-rot fungi. Once decay sets in, the wood loses strength from the inside out. Old trees full of borer holes often snap in high wind.
Wild black locust also carries sharp thorns. Paired spines sit at the base of each leaf, and they can puncture a tire or cut a hand during pruning. Honey locust, a cousin, grows even longer thorns on its trunk. Kids and pets pay the price when these trees ring a play area.
Invasive Spread
- Noxious-weed status: Several states list black locust as invasive, so it can crowd out native plants along field and forest edges.
- Fast colonizer: The tree grows quick and reseeds itself, which lets one planting take over open ground in a few seasons.
- Hard to contain: Roots reach far past the trunk and push shoots into lawns, gardens, and a neighbor's yard.
Aggressive Suckering
- Clonal thickets: New stems rise straight from the roots, so one tree becomes a tight cluster of trunks over time.
- Worse after cutting: Chopping the tree down sets off a flush of new suckers, and stumps resprout with force.
- Wide reach: Suckers can appear 20 feet or more from the parent trunk, well past any bed edge.
Toxic Parts
- Poison in bark and seeds: The bark, leaves, and seeds of black locust hold compounds toxic to people, horses, and livestock.
- Risk to animals: Horses that chew the bark or swallow seed pods can get sick, so fencing near these trees helps.
- Not the flowers: The white spring blooms are the one part cooks use, while the rest of the tree stays off the plate.
Brittle Limbs
- Storm damage: Branches weakened by borers and decay snap in wind and drop on whatever sits below.
- Weak crotches: Fast growth leaves narrow branch joints that split under ice or a heavy load of leaves.
- Cleanup work: You end up raking twigs and hauling fallen wood after most big storms.
Weigh these locust tree problems against the perks before you plant. Locust fixes nitrogen in the soil, feeds bees with heavy spring bloom, and gives you rot-proof wood for posts. For a tidy yard, skip the wild seedlings and pick a sterile, thornless cultivar instead. These stay put and drop no seed pods, so you dodge most of the suckering and thorns.
Check your local rules before you buy a black locust. Some counties ban or limit it because of how fast it spreads. If you already have a problem tree, hold off on random cutting, since that only feeds more suckers. Turn to a full removal guide for the right steps to take one out for good.
Read the full article: Locust Tree: Honey vs Black Locust Guide
