Do Honey Locust Trees Have Thorns?
The honey locust tree, Gleditsia triacanthos, is a widespread deciduous tree native to central North America. This tree is recognized for its distinctive appearance and adaptability, thriving in various environments. The presence of thorns is a frequent question regarding this species. While many honey locust trees are characterized by formidable thorns, there are also cultivated varieties that lack this feature.
Characteristics of Honey Locust Thorns
Honey locust trees, particularly those found in the wild, possess prominent thorns on their trunks and branches. These thorns are stout, sharp, and range in length from approximately 2.5 to 8 inches (6–20 cm). They commonly appear as single structures or are branched into several points, often forming dense clusters. The thorns are reddish-brown and found along the main trunk and lower branches, defending the tree.
The arrangement of these thorns can vary, with some appearing in groups of three or more, making them formidable. These woody structures are modified stems, and occasionally, small leaves may sprout from them. The presence of these sharp, robust thorns makes the wild honey locust easily identifiable and can pose a hazard, which is why the species is not recommended for urban or suburban landscapes.
Purpose and Varieties
The thorns on honey locust trees serve a primary biological purpose: defense against large browsing animals. It is believed that these oversized thorns evolved to protect the trees from megafauna, such as mastodons, that roamed North America during the Pleistocene epoch. Even today, these thorns deter animals like squirrels, opossums, and deer from browsing on the tree’s bark and leaves. This defensive mechanism allowed the trees to survive and thrive by preventing herbivory.
Despite the natural presence of thorns, a thornless variety exists, known as Gleditsia triacanthos var. inermis. This variety occurs naturally in the wild, though it is less common than its thorny counterpart, and has been widely cultivated for landscape use. Horticulturists have developed numerous thornless cultivars, making the honey locust a popular choice for urban plantings, street trees, and residential landscapes where the sharp thorns would be undesirable. These cultivated thornless forms offer the tree’s other beneficial qualities, such as its tolerance to various soil conditions, drought, and urban environments, without the hazard of its characteristic spines.