Is a Honey Locust Tree Poisonous?

Honey locust (Gleditsia tricanthos) grows native to the United States, from central Pennsylvania southwest to Louisiana, westward to central Texas and north to states such as Iowa and eastern Nebraska. While the tree is not poisonous, that does not mean it does not present certain problems if you opt to use it in your landscape.

The main ornamental feature of the honey locust is its compound foliage, composed of a main stem as long as 8 inches and many small leaflets, as tiny as 3/8 of an inch long, attached along it. The foliage and the tree's ability to grow in tough conditions make it a possible shade or street tree, but its increased use for such purposes translates into more insects becoming aware of its potential as food. Pests particular to the honey locust include the mimosa webworm. Spider mites also attack a honey locust, with the capacity to eat all the leaves during a heavy infestation. Scales, woodborers and certain moths also will make a meal out of parts of the honey locust. The species is highly resistant to disease, with certain fungal ailments causing wood rot and some leaf maladies marring the appearance of the foliage, according to the National Forest Service.

The flowers of the honey locust, shaped like bells, emerge in May or June and are greenish-yellow. They make no significant ornamental contribution to your landscape, yielding a long seedpod resembling a hanging strap. The seedpods are between 7 and 18 inches in length, slightly twisted and they turn from green to shades of brown. They will hang onto the tree into the winter. The tree takes its name from the sweet, gum-like substance in the pods. The pods are edible, with the "National Audubon Society Field Guide to Trees: Eastern Region" noting livestock and many forms of wildlife consume the pods with no ill effects. Creatures such as white-tail deer, opossums, crows, gray and fox squirrels, and hogs feed on these pods, which have a protein content of as much as 13 percent.

The seedpods of the honey locust can grow in great numbers on the tree, making the tree unattractive once the leaves fall off and the scraggly, brown pods are the only thing left on the limbs. When these pods do fall from the honey locust, they collect underneath the tree. This creates a mess, requiring you to expend plenty of energy as you rake them up and haul them away.

The pods are a potential eyesore, but the thorns of the honey locust present a real danger. The trunk of a honey locust, as well as the branches and the twigs, feature sharp spines. Coming into contact with these thorns,is not a pleasant occurrence. One potential solution to the problem of thorns is to choose a cultivar of honey locust lacking these spines. "Moraine" is such a tree, according to the University of Connecticut Plant Database. Moraine has no thorns, nor does it produce fruit, growing to 40 feet and turning yellow in autumn.