Thornless Honey Locust care — light, water, toxicity and hardiness
Thornless Honey Locust (Gleditsia triacanthos var. inermis) wants full sun and a drink about every 10 days once established. It is hardy in USDA zones 4 to 9. It is safe to have around pets.
| scientific name | Gleditsia triacanthos var. inermis |
|---|---|
| family | Fabaceae |
| category | tree |
| plant type | perennial |
| light | full sun |
| water cadence days | 10 |
| mature height cm | 2000 |
| min zone | 4 |
| max zone | 9 |
| frost tolerant | true |
| toxic to pets | false |
| toxic to humans | false |
| edible | false |
How often should I water Thornless Honey Locust?
Light, dappled shade grass grows under.
Who eats it
Palatable to browsing animals such as deer: medium. Palatable to grazing animals: low. Palatable to people: no.
What it needs
Its shade tolerance is high. Its moisture use is medium. Its drought tolerance is high. It wants at least about 20 inches of rain a year. Above roughly 70 inches of annual rain it struggles. It tolerates soil down to pH 5.0. It tolerates soil up to pH 8.0. Its fertility requirement is medium. Adapted to coarse, sandy soils: no. Adapted to medium, loamy soils: yes. Adapted to fine, clay soils: yes. Its tolerance of waterlogging is low. It needs at least 150 frost-free days. Its salt tolerance is medium. Its tolerance of chalky soil is medium. Its fire tolerance is medium. Fire resistant: no. It has been recorded down to -36°F. It suppresses neighbours chemically: no.
How it grows
It grows as a single stem form. Its growth rate is rapid. Its lifespan is moderate. It puts on most of its growth in spring and summer. It spreads by seed at a slow rate. It resprouts after damage: yes. Coppices: yes. Its tolerance of hedging is low. At maturity it reaches about 70.0 feet. By twenty years it is about 35 feet. Its roots go down at least 48 inches. Its shape is rounded. It holds its leaves through winter: no.
What it looks like
It blooms in late spring. The flowers are yellow. Conspicuous in flower: no. The foliage is green. The foliage texture is medium. In summer the canopy is moderate in porosity. In winter it is porous in porosity. Fall colour: yes. The fruit or seed is green. Fruit begins in summer. Fruit finishes by fall. It fruits medium. The fruit persists on the plant: yes. The fruit is conspicuous: yes.
Growing more of it
Propagated by seed: yes. Propagated by cuttings: yes. Propagated by container: yes. Propagated by bare root: yes. Propagated by bulb: no. Propagated by corm: no. Propagated by tubers: no. Cold stratification required: no. Seedling vigour is medium. Commercial availability: routinely available.
Source: Drafted from US Cooperative Extension horticulture guidance; pending HUMAN-05 review (issue 280) · ASPCA Toxic and Non-Toxic Plant List · 2026-09-02