A medium-tall native legume tree with finely divided compound leaves and (in wild form) terrifyingly long branched thorns on the trunk. Long sugary seed pods feed wildlife.

Also called: Sweet Locust, Thorny Locust

Native status: Native to central and eastern US

§ Quick facts

SizeMature height 20–30 m (65–100 ft); trunk diameter 0.6–1.2 m
WeightN/A
Lifespan100–120 years
OrderFabales
FamilyFabaceae

§ Encyclopedia

The honey locust, also known as the thorny locust or thorny honeylocust, is a deciduous tree in the family Fabaceae, native to central North America where it is mostly found in the moist soil of river valleys. Honey locust trees are highly adaptable to different environments, and the species has been introduced worldwide. Outside its natural range it can be an aggressive, damaging invasive species.

Source: Wikipedia — Honey locust Licensed under CC BY-SA 4.0

§ Identification

Field marks. Medium-large tree with finely divided fern-like compound leaves; long branching thorns on trunk and branches; flat curving brown seed pods (15–35 cm); inconspicuous greenish-yellow flower clusters.

Similar species. Black Locust (different thorn pattern, larger leaflets, white flowers). Mesquite (smaller, southwestern). Kentucky Coffeetree (no thorns).

Voice. N/A

§ Diet & behavior

Diet. N/A — photosynthesis; legume; nitrogen-fixing root nodules

Behavior. Native bottomland tree with formidable defensive armament — branched thorns up to 10 cm long covering trunk and branches. Thorns are believed to be defenses against now-extinct Pleistocene megafauna (mastodons, giant ground sloths). Long brown twisted seed pods filled with sweet pulp were eaten by megafauna and dispersed seeds; in their absence, pods now rot under parent trees. Thornless cultivars are widely planted as urban shade trees.

§ Range

Central US

§ Habitat

Bottomlands, fields, urban plantings

§ Threats

Loss of bottomland forest, replacement with thornless cultivars (often inferior wildlife).

§ Conservation status

According to the IUCN Red List, the honey locust is currently classified as Least Concern.

§ What helps

Plant thorny (not just thornless) cultivars for wildlife. Maintain bottomlands. Tolerate seed pods.

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§ Further reading

§ Sources cited

  • USDA Plants Database
  • Pleistocene megafauna seed dispersal hypothesis (Janzen and Martin 1982)
  • USDA Forest Service Silvics Manual