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.
Size and Form:
Thornless honeylocust 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 color and texture:
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 or needle arrangement, size, shape, and texture:
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 arrangement, shape, and size:
Inconspicuous, small, yellow-green flowers form in spikes in spring.
Fruit, cone, nut, and seed descriptions:
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).
Plant care:
Prune in fall or winter.
List of pests, diseases, and tolerances:
Mites can lead to early leaf drop. Cankers, root rot, and borers are potential problems (most commonly on stressed trees). Tolerant of black walnut toxicity.
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.
Sunburst thornless honey-locust (Gleditsia triacanthos f. inermis ‘Suncole’):
New foliage emerges yellow and matures to bright green. A seedless, male cultivar.
