Gleditsia triacanthos var. inermis (gle-dit’-se-a try-a-kan’-thus ee-ner’-mis)
Family: Caesalpinaceae, Cassia; Formerly Fabaceae, bean family)
Key Steps
- 1b – Alternate leaf arrangement — go to 18
- 18b – Leaf compound — go to 58
- 58b – More than 3 leaflets — go to 59
- 59a – Entire or very finely serrate leaflet margins — go to 60
- 60a – Thorns — go to 61
- 59a – Entire or very finely serrate leaflet margins — go to 60
- 58b – More than 3 leaflets — go to 59
- 18b – Leaf compound — go to 58
Description
Leaf: Oddly pinnate or bipinnately compound. 20-30 oblong leaflets, each 1-2 inches long, broadest at base, rounded or blunt at base and tip. Hairy on central vein beneath, hairy petiole. Very fine toothed margin. The whole leaf is 6-15 inches long. Base of petiole swollen, enclosing bud. Leaflets usually have no leafstalk. Leaves may be clustered towards branch tip.
Bud: Hairless, usually embedded into the stem, making the bud very hard or impossible to see. Smaller buds may be above larger ones. True terminal bud absent.
Leaf Scar: Hard to see. Roundish with 3 bundle scars. Surrounds buds.
Stem: Stout. Native Honeylocust may be armed with long thorns that are actually modified branches. (Most Honeylocust in the landscape are thornless – “inermis”.) Zig-zaggy branching. Shiny, smooth, reddish-brown brittle. Mottled or streaked. Very knobby. Enlarged leaf nodes.
Bark: Mostly smooth, but round in spots, as if smoothed by a trowel.
Pith: Round, continuous, pale or pinkish.
Flower: Small, greenish-yellow. Fragrant. Blooms in May or June.
Fruit: Brownish-red, flat, slightly curved, 6-16 inch long, leathery pod. Seeds rattle inside.
Habit: Large, open canopy. Horizontal, zig-zagging branches. 50 feet by 40 feet.
Culture: Moderate moisture requirement. Tolerant of mild soil compaction making it the most used sidewalk tree. Full sun. Greatly overused in urban landscapes.
Cultivars:
- Fairview — 40 feet tall by 40 feet wide. Fruitless.
- Imperial — 30 to 35 feet tall. Thornless, round crown, some fruit.
- Moraine — 40-50 feet tall by 45 feet wide. Fruitless. Darker green leaves
- Shademaster — 70 feet tall by 50 feet wide. Ascending branches, dark green leaves, may have some pods.
- Skyline — 45 feet tall by 35 feet wide. Compact, ascending branches. Pyramidal. Dark green leaves.
- Sunburst — 30-35 feet tall. New growth golden, changing to bright green. Needs regular irrigation. Extremely prone to Honeylocust Seed Pod Gall Midge.
Resources
