Thorn trees thrive in a tropical to semi-temperate climate including East Texas's humid subtropical climate. Thorn trees have spike-like thorns that grow on the branches of the tree. The thorns protect the tree from predatory animals. Thorn trees come from the plant family Fabaceae, which includes locust, lycium, mesquite and acacia tree species.
The roemer acacia (Acacia roemeriana) is a leguminosae tree that is a semi-evergreen to evergreen plant. This tree grows to reach heights of 15 to 20 feet, which classifies it as a shrub or small tree. The tree needs deep alkaline soil to develop to its maximum height. Roemer acacia trees thrive in Edwards County in the eastern portion of Texas. In the limestone soils in Edwards County, the roemer acacia is 3 to 6 feet in height only. The roemer acacia has a spread of 15 feet in width. The branches of the tree have spine-like thorns. This type of tree needs full sun and is a cold hardy drought resistant plant. The roemer acacia blooms during the spring with clusters of round white to greenish white flowers. The flowers have five petals and long stamens. The fruit grows from flat pods.
The mesquite tree (Prosopis glandulosa var. glandulosa) is widely spread throughout Texas including east Texas. This deciduous tree is a leguminosae plant that provides shade for animals. The tree has a height of 30 feet and a width of 40 feet. This mesquite tree thrives in full sun and has a high tolerance for drought. The mesquite tree adapts to any type of soil. During the spring through fall seasons, the mesquite tree flourishes with 3- to 5-inch long pendulous creamy white fragrant flowers. The branches of the mesquite tree develop 2-inch long thorns, which have the ability to injure livestock. Some commercial uses for the mesquite tree include manufacturing the bark for wood flooring and furniture making.
The honey locust (Gleditsia triacanthos) is a deciduous leguminosae tree. This deciduous tree thrives in full sun and the fertile soil of East Texas. The honey locust is not a favorite among landscapers because of the tree's 12-inch long thorns that adorn the vase-shaped branch. For landscaping use, there is a variety of the honey locust tree without thorns. The tree's height ranges from 50 to 100 feet tall and has a width of 25 to 50 feet. The honey locust has a high tolerance for heat and a medium threshold for drought. In the spring, the honey locust develops green flowers. The fruit of the tree is 6 to 18 inches long with a twisted flat pod.