Common Thornless Honeylocust

Arbor walk #78, Treekeeper ID #3229

The Honeylocust is a tough, medium-sized shade tree that usually grows around 60′ to 80′ tall. It has greenish-yellow to greenish-white flowers that appear in May or June. This is an adaptable tree well suited for streets and parking lots.

The ‘Skycole’ cultivar is a relatively old line dating from 1957. It was bred for use in cities and streetscapes. This variety is thornless, nearly seedless, and its leaves turn an attractive yellow color in the fall. Another great feature of this variety is that the ‘Skycole’ cultivar does not require much water and is heat tolerant. This makes it a perfect tree to plant for community foresters and college campuses.

More infromation on the Common Thornless Honeylocusts in our Arboretum here!

Common NameCommon Thornless Honeylocust
Latin NameGleditsia triacanthos f. inermis
Indigenous Name(s)
Cultivar/Variety ‘Skycole’
Commercial NameSKYLINE
Global Distribution
Where to find Arbor Walk #78 on WashU campus
Our Common Thornless Honeylocust in space
GPS Coordinates

N/A

Percent Concrete

N/A

Distance to Buildings
YearClose Building #1Close Building #2Close Building #3
2020Umrath House, 7.69 mZetcher House, 10.26 mRisa Commons, 23.38 m
Distance to Other Species
YearClose Species #1Close Species # 2Close Species # 3
2020Honeylocust, 9.01 mHoneylocust, 9.15 mHoneylocust, 13.23 m
Our Common Thornless Honeylocust through time
Standard Measurements
YearHeight (m)DBH (cm)Crown Diameter N-S (m)Crown Diameter E-W (m)Average Crown Diameter (m)
20206.238.103.123.273.195
20238.9411.76.367.076.715
Nests and Pests
YearDescription
2020Two old pruning wounds have dark fungus/algae/bacteria on the exposed wood, but appear to be healing normally otherwise
One oddly-shaped scar
Light presence of dark green algae
Grey lichen
How to identify a Common Thornless Honeylocust
Leaf Identification

The Common Thornless Honeylocust has even-pinnately compound leaves with 15 to 30 lanceolate leaflets. The leaflets are usually 1/2″ to 2″ long. The margins are crenated to serrated, and the venation is pinnate. They are a bright green and turn yellowish-gold in the fall. The leaves are sometimes bipinnately compound, but this form is much more common in younger trees.

Twig and Bud Identification

The twigs of the Common Thornless Honeylocust typically zig zag, are reddish- or grayish-brown, and have lighter lenticels. Even though this is a thornless variety, sometimes the twigs will develop thorns. The lateral buds are small and sunken. It has no true terminal bud.

Bark Identification

The Common Thornless Honeylocust has dark gray bark with very long, defined plates. Young trees will have smooth bark with numerous lenticels (pores).

Fruit Identification

The fruit of the Common Thornless Honeylocust are purplish-brown seed pods. They are typically 6″ to 8″ long, flat, and coiled.

Flower Identification

The flowers of the Common Thornless Honeylocust are greenish-yellow and hang in 2″ to 3″ long clusters. They are racemes, or flowers on tiny pedicels (stalks) off a main upright inflorescence (flowering stem).

‘Skycole’ Identification

This is a male cultivar that has a more pyramidal shape. Since it is male, it will never produce fruit.

Relationship of Gleditsia triacanthos f. inermis to other species in the arboretum
Additional resources on the Common Thornless Honeylocust

Take a look around Arbor Walk Tree #78