Thornless honey-locust | Gleditsia triacanthos f. inermis

The light, dappled shade cast by the lacy foliage of thornless honey-locust is only one of its virtues. It also is durable and adaptable, tolerating a wide range of soil conditions as well as drought, and road salt, and has a lovely yellow fall color. As a result, honey-locust is somewhat overused in city and suburban landscapes. For the sake of species diversity, it should only be planted after consideration of alternatives.

The native species of honey-locust has large thorns on its stems and bark. For this reason, thornless honey-locust is most commonly sold.

Family (English) Pea
Family (botanic) Fabaceae (formerly Leguminosae)
Planting site City parkway, Residential and parks, Restricted sites, Wide median
Tree or plant type Tree
Foliage Deciduous (seasonally loses leaves)
Native locale Chicago area, Illinois, North America
Size range Medium tree (25-40 feet), Large tree (more than 40 feet)
Mature height 30-70 feet
Mature width 30-70 feet
Light exposure Full sun (6 hrs direct light daily)
Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9, Zone 10
Soil preference Moist, well-drained soil
Drought tolerance Tolerant
Other tolerances Alkaline soil, clay soil, Dry sites, Road salt, Wet sites
Season of interest early fall, mid fall
Flower color and fragrance Inconspicuous
Shape or form Broad, Round
Growth rate Fast
Transplants well Yes
Planting considerations Commonly planted
Wildlife Game birds, Migrant birds, Small mammals
Has cultivars Yes

More Information

Size and Form

Thornless honey-locust gets 40 to 70 feet tall and wide. It has a rounded form.

Native Geographic Location and Habitat

Native to most of the lower Midwest and south to the Gulf coast. C-Value: 2.

Bark Description

Bark is dark gray, breaking into long flat plates that curl along the edges. The native honey-locust has long thorns on stems and bark; f. inermis does not.

Leaf Description

Leaves are alternate and pinnately compound or bi-pinnately compound, with 20 to 30 oval leaflets. Each leaf is about 6 to 8 inches long. Fall color is yellow.

Flower Description

Inconspicuous, small, yellow-green flowers form in spikes in spring.

Fruit Description

The fruit is a flat, red-brown pod (legume), about 1 inch wide and several inches long. It is often curling. Each pod contains several seeds. Some cultivars are fruitless (seedless).

Cultivars

These plants are cultivars of a species that is native to the Chicago Region according to Swink and Wilhelm’s Plants of the Chicago Region, with updates made according to current research. Cultivars are plants produced in cultivation by selective breeding or via vegetative propagation from wild plants identified to have desirable traits.

Imperial™ thornless honey-locust (Gleditsia triacanthos f. inermis ‘Impcole’)

A more compact cultivar (35 feet) that produces a few seed pods.

Moraine thornless honey-locust (Gleditsia triacanthos f. inermis ‘Moraine’)

This tree is a seedless male cultivar. It has a graceful outline, with small dark green foliage that turns golden yellow in fall.

Northern Acclaim thornless honey-locust (Gleditsia triacanthos f. inermis ‘Harve’)

A seedless male cultivar, considered cold hardy to zone 3, this cultivar has good yellow fall color. Drought tolerant; 45 feet tall.

Perfection thornless honey-locust (Gleditsia triacanthos f. inermis ‘Wandell’)

A seedless male cultivar with good branch structure, growing to approximately 50 feet tall.

Skyline thornless honey-locust (Gleditsia triacanthos f. inermis ‘Skycole’)

A male (fruitless) cultivar with a more pyramidal shape.

Street Keeper™ thornless honey-locust (Gleditsia triacanthos f. inermis ‘Draves’)

Narrow, upright form maturing to a 20 foot spread, this cultivar will produce some seed pods.