The Honey locust (Gleditsia triacanthos) is a deciduous tree native to North America. It is mostly found in the moist soil of river valleys from southeastern South Dakota south to New Orleans and east to central Pennsylvania. It is also naturalized in parts of southern Europe.

Honey Locust thorns

Honey Locust seed pods

Honey locusts can reach a height of 20-30 meters (66-100 feet). They grow quickly, which make them useful plantings in areas where shade is wanted quickly, such as new parks or housing developments, and in disturbed and "reclaimed" environments, such as former surface mines. They are relatively short-lived, however, living about 120 years. They are also prone to losing large branches in windstorms.

Honey locusts commonly have long, branching thorns growing out of the twigs and branches, however the thorns may be single, or forked into three barbs. It has been suggested that these thorns evolved to protect the trees from now-extinct large animals (which may have been the distributor of its seeds, eating the pods whole and passing out the seeds intact.) In the past, the hard thorns of the younger trees have been used as nails. Thornless forms (f. inermis) are occasionally found growing wild, and have been widely selected for horticultural use.

The leaves are pinnately compound on older trees but bipinnately compound on vigorous young trees. The leaflets are 1.5-2.5 cm long (smaller on bipinnate leaves) and bright green. They turn yellow in the fall. The strongly scented cream-colored flowers appear in late spring, in clusters emerging from the base of the leaf axils.

Honey Locust produces a flat pod fruit that matures between September and October. The pods are generally between 15-20 cm long and can be fermented to make beer. The pulp on the insides of the pods is edible and sweet; however, it should not be confused with Black locust, which is toxic. Interestingly Honey locust is not a significant honey plant, while Black locust honey is prized.

This tree's thornless form and it cultivars are popular in cultivation, expecially in the northern plains of North America where few other trees can survive and prosper. This tree tolerates urban conditions, compacted soil, road salt, alkaline soil, heat and drought. This tree's populatrity is in part due to the fact that it transplants so easily. This tree is resistant to Gypsy moths but is defoliated by another pest, the Mimosa webworm . Spider mites, cankers, and galls are a problem with some trees.

The genus contains 12 other species, native to Asia and other areas of North America; see Gleditsia for details.

References

• Sternberg, Guy, (2004) Native Trees for North American Landscapes pp. 264. Timber Press, Inc.