Gleditsia triacanthos, commonly called honey locust, is native from Pennsylvania to Iowa south to Georgia and Texas. It typically grows 60-80’ (less frequently to 120’) tall with a rounded spreading crown. Trunk and branches usually have stout thorns (to 3” long), but ours are 'thornless'. In reality, most are just significantly more thorn-free than most of the species. The inconspicuous, greenish yellow to greenish white flowers appear in racemes in late spring and are delightfully fragrant. The flowers are followed by long, twisted and flattened, dark purplish-brown seedpods (to 18” long) which mature in late summer and persist well into winter. Seedpods contain, in addition to seeds, a sweet gummy substance that gives honey locust its common name.
It is best grown in organically rich, moist, well-drained soils in full sun, but is tolerant of a wide range of soils, as well as wind, high summer heat, drought and saline conditions. Bees enjoy its nectar, although the nectar flow can be brief.
The genus name honors Johann Gottlieb Gleditsch (1714-1786), the director of the Botanical Garden, Berlin, while the species epithet comes from the Greek acantha meaning thorn and tri meaning three in reference to the three-branched thorns on species plants. (Courtesy of: Missouri Botanic Garden)
The honey locust has a number of applications: its fruit is used in agriculture to feed livestock; its dense wood is used to make furniture and fences; and its unique compounds may have medicinal uses for treating diseases like rheumatoid arthritis and cancer.
As honey locust is in the legume family, it is assumed that the roots fix nitrogen; however, no root nodules have been observed. However, many popular sources, such as permaculture publications, claim that Gleditsia does fix nitrogen but by some other mechanism. There seem to be data that support this hypothesis, including electron microscopy and protein analyses, but thus far, no consensus has been arrived at.
The fast growth rate and tolerance of poor site conditions make it valued in areas where shade is wanted quickly, such as in new parks or housing developments, and in disturbed and reclaimed environments, such as mine tailings. It is resistant to gypsy moths but is defoliated by another pest, the mimosa webworm (Wikipedia).