Spineless Honey Locust

Gleditsia triacanthos
Family: Fabaceae (pea family)
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Locust Tree
Locust Bark
Locust Leaf
Locust Flowers www.mwrop.org


Angiosperm, Dicot, deciduous


14-25 meters tall with a trunk up to .8 meters in diameter

Identifying Features:

  • Leaves are alternate, odd pinnately compound with 7 to 19 leaflets.
  • The leaves of young trees are bipinnate
  • The bark is dark grey-brown and deeply furrowed with flat topped ridges
  • Twigs are red-brown and zigzag shaped with lighter lenticels. There are paired spines at each leaf scar.
  • On young trees the bark is smooth and greenish-brown in color


  • The eastern section of the original native range of the black locust is centered in the Appalachian Mountains and ranges from central Pennsylvania and southern Ohio to northeastern Alabama, northern Georgia, and northwestern South Carolina. The western section includes the Ozark Plateau of southern Missouri, northern Arkansas, and northeastern Oklahoma. It is also found in the Ouachita Mountains of central Arkansas and southeastern Oklahoma, as well as in southern Indiana and Illinois.
  • It has been widely planted and naturalized throughout the United States, as well as in parts of Canada and Europe
  • Thrives in moist limestone soils
  • Grows best in mixed mesophytic forests


  • White, fragrant, nectar bearing flowers that grow in hanging clusters and appear in mid to late spring
  • Flowers are monoecious, meaning that some are male and some are female
  • Pollinated by bees and other insects
  • Fruit is a light brown flattened legume containing 4-10 smooth, red brown seeds
  • Fruit ripens in autumn and hangs on the tree, gradually dispersing its seeds until early spring
  • Seed production begins at age 6
  • Seed production is best between 15 and 40 years and continues until age 60
  • The Black Locust tree may also reproduce through root suckering and stump sprouting, especially if cut or damaged

Water/Sun Requirements:

  • Requires well drained soil
  • Prefers full sun but can grow in partial shade
  • Intolerant of full shade and herbaceous competition
  • Does not do well in excessively dry soils

Special Adaptations:

  • Nitrogen fixing
  • Rapid juvenile growth
  • Able to tolerate drought, salt and poor soil
  • Tolerates pollution well
  • Seeds germinate by scarification
  • Every part of the tree except for the flowers is poisonous
  • Bark is especially poisonous and cattle often die from browsing on it; small children can become ill from chewing on bark or twigs

Other Info:

  • 17th century Jesuit missionaries named it the "locust" tree because it reminded them of the locust that John the Baptist ate in the Bible
  • It can become an invasive species outside of its natural range, especially in dry and sand prairies, oak savannas, and upland forest edges
  • It was one of the first New World trees to be planted in Europe
  • Often planted as erosion control
  • Widely planted as an ornamental
  • Used for land reclamation because of its nitrogen fixing capabilities
  • It is a major honey plant in the eastern USA and parts of Europe
  • Not a commercial timber species, but it can be used for fuel wood and pulp
  • Wood is resistant to rot and is often used for railroad ties and fence posts
  • Can be severely damaged by insects such as locust borers and locust leafminers
  • It often suffers from heart rot and witches broom disease, which are caused by the virus Chlorogenus robiniae. It can also be infected by Phymatotrichum omnivorum, which causes root rot, and Nectria cinnabarina.
  • Other common plant diseases that it is susceptible to are canker, leaf spot, and powdery mildew.
  • The seedpods are edible when cooked because the toxins are destroyed by heat
  • Cherokee Indians chewed the root bark to induce vomiting
  • The flowers contain glycoside robinin, which acts as a diuretic

Reference Sources/Links:


Created by Celsiana W. 2007