If you’ve got a large garden, go ahead and plant a Gleditsia triacanthos, you’ll savor its cool shade during summer. And, you’ll marvel at the honey locust‘s sweet fall fruit pods in fall and winter.
Gleditsia triacanthos key facts
| Botanical name | Gleditsia triacanthos |
|---|---|
| Family | Fabaceae |
| Type | Tree |
| Height | Up to 90 feet (30 m) |
| Exposure | Sun to part shade |
| Soil | Fertile, well drained |
| Hardiness | Hardy 5 to 23°F (-5 to -15 °C) |
| Growth | Average to fast |
| Foliage | Deciduous |
| Fruit formation | End of summer, fall |
| Flowering | Beginning of summer (insignificant) |
Common names: Honey locust, sweet bean tree, honey shucks locust, thorny locust…
The list says it all: thorns, sweet fruits… an interesting mix!
This tree is native to North America. The plus-sized growth of this tree and its magnificent foliage make this tree a welcome haven of shade to fight off extreme summer heat. The most significant point – literally – of honey locust are the many thorns along the trunk and branches.
The small panicle-like flowers of Gleditsia triacanthos aren’t beautiful, not in themselves. But they do turn into surprising giant seed pods that are very ornamental. These pods even hang to the tree long after leaves have dropped in fall. In addition, these fleshy pods are a boon for cooking: their sweet flesh is edible and you can use it to directly replace sugar.
The more adventurous among us can even try to ferment it to brew beer.
Leaves of honey locust are somewhat similar to those of black locust. They’re up to 8 inches long (20 cm), with many oval leaflets. When fall comes around, they slowly take on a gold-yellow hue.
Did you know… ? The elegant Gleditsia triacanthos is sometimes also called Thorns of Christ: it’s said that the Crown of thorns that Jesus wore during the passion was wrought from this tree’s branches.
Nurseries rarely sell the thorny wild form: almost all garden trees belong to the thornless inermis group. Here are the selections you are most likely to meet, chosen on size, habit and leaf colour.
| Variety | Height at maturity | Foliage | Habit and use |
|---|---|---|---|
| ‘Sunburst’ | About 12 m | Bright golden-yellow young shoots, greening later | Broad rounded crown, thornless, produces few or no pods |
| ‘Rubylace’ | About 10 m | Deep bronze-red new growth, fading to bronze-green | Small spreading tree, thornless, good for a feature lawn specimen |
| ‘Skyline’ | 12–15 m | Fresh green, clear yellow in autumn | Upright pyramidal, thornless and virtually podless, avenue planting |
| ‘Elegantissima’ | 3–4 m | Fine bright green leaflets | Slow, shrubby and bushy, thornless, suits smaller gardens |
| ‘Halka’ | 12–14 m | Mid-green, yellow in autumn | Rapid vase-shaped growth, thornless, near-podless, parks and avenues |
Branches of Gleditsia triacanthos are rather fragile, so it’s best to find a spot for it that is sheltered from strong winds. As for the soil, make sure it drains well enough, is deep and rich with lots of organic matter. Soil pH won’t matter. Regarding exposure, the sweet bean tree prefers sunny spots, though it can still make do with part shade.
Older trees are hardier and won’t suffer much from the cold, but younger plants aren’t as resistant. In addition, honey locust deals pretty well with drought. As a consequence, the best time to plant your tree is at the beginning of spring. If needed, though, you can still of course plant in fall, but you’ll have to protect the tree during that first winter.
After selecting the right spot, simply:
You can get new thorny locust specimens either through seeds (sow in fall) or by grafting (shield grafting) at the end of summer.
Thorny locust does require a little bit of maintenance during the first few years of growth:
A resilient tree, honey locust isn’t vulnerable to diseases, nor does it fall victim to parasite insects and pests.
The massive size of Gleditsia triacanthos means it can only fit in large gardens and parks.
It can grow there as a standalone or in a row, alongside a road or walkway.
Since it resists pollution very well, it even serves to decorate streets.
