Honey locust

Gleditsia triacanthos L.

Family: Fabaceae

Pet & Human Safety

People: Skin irritant to peoplePets: Not on the ASPCA lists as we read them

Hazardous parts

thorns on trunk and branches

Preparation

n/a

Hazard type

physical injury (puncture)

Hazard route

skin (puncture wounds)

How complete this information is

The safety information on this page is partial. Where a source covers a point, it is shown; where none does, the page says so.

Toxic to pets

No ASPCA entry found.

ASPCA lists honey locust (Gleditsia triacanthos) as non-toxic to dogs, cats and horses. ASPCA is the only source we found, and one source is not enough to call a plant safe for pets, so it is not assessed as safe. Keep pets from eating it. The thorns on wild-type trees are still a physical hazard.

PlotAndPetal cannot tell you whether a plant you found can be eaten. Only someone who can see the plant can identify it.

Look-alike warning

Could be mistaken for Other plants with a similar name or look. To tell them apart: Match on the scientific name, Gleditsia triacanthos L., not on the common name.. Honey locust, sweet locust, thorny locust and 'three-thorned acacia / acacia de tres espinas' are names that overlap with 'locust' and 'acacia' plants that are different species, including black locust (Robinia pseudoacacia, which NC State Plant Toolbox rates as poisonous in bark, leaves and seeds to people, dogs, cats and horses) and true Acacia. Do not treat guidance for one as guidance for another; use the binomial.

Poison control

If someone has collapsed, cannot be woken, is having a seizure or has trouble breathing, call 911 now. For any other possible poisoning, call Poison Help: 1-800-222-1222.

Emergency number source: U.S. federal law (47 U.S.C. § 251(e)(3)), read 2026-10-07.

Naturalist Lore

Historical Background & Breeding Lore

The history of this plant and its name, and how it was bred, where we have them.

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Care

Hardiness zones: USDA 3a-8b per NC State; USDA 3-8 per UMN; USDA 5-8 per Univ. of Illinois (thornless form); USDA 3-9 per Utah State; USDA zone 4 per Univ. of Kentucky; USDA 4 to 10a per INRAE (France source, labelled USDA); RHS H6 per RHS (UK, about -20 to -15 C)
Light: Full sun preferred; tolerates part shade, not full shade (NC State).
Water needs: low
Mature size: height: 60-80 ft (NC State, UMN); 40-70 ft thornless form (Illinois); about 70 ft (Virginia Tech); 30-70 ft, 100 ft or more in the wild (Kentucky); over 12 m, 30 m or more (RHS); 15-25 m (INRAE); up to 24 m (MITECO); width: 60-80 ft (NC State, UMN); about 50 ft (Virginia Tech); 30-70 ft (Kentucky); wider than 8 m (RHS)

Soil & Drainage

Pruning & Flush Rhythm

Feeding Schedule

How to prepare the soil, when and what to feed, and how and when to prune where that applies.

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