Common Name: Water Locust

General Information

Gleditsia aquatica is a deciduous tree with stout, spreading branches forming a rather irregular top; it usually grows 15 - 18 metres tall, sometimes reaching 25 metres, though it is often a multi-stemmed shrub when cultivated outside its native range. The bole can be 60 - 75cm in diameter. The trunks and branches are armed with branched spines up to 10cm long[, , ].
The plant is harvested from the wild for local use as a source of wood. It is used in soil stabilization projects and is also grown as an ornamental.

Known Hazards

None known

Botanical References

, ,

Range

South-eastern N. America - Missouri to Indian and S. Carolinaa, south to Texas and Florida

Habitat

Rich lands of river valleys that are subject to inundation, often for a considerable part of the year[, ]. Swampy areas , along streams, bottomland woods[].

Properties

Other Uses Rating
Habit	Deciduous Tree
Height	12.00 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Gleditsia aquatica is fairly cold-hardy, with older trees being able to tolerate temperatures down to around -20°c when fully dormant. The tree has a habit though, especially when young, of producing new growth until quite late in the season. Especially in areas where the summers are not hot, this new growth will not ripen fully and will be liable to be cut back by the cold in the winter. Older plants tend to lose this habit. Generally, the plant should be considered to only be hardy to about -5°c when young, especially if growing in areas with cooler summers[].
Easily grown in a loamy soil, requiring a sunny position[]. Succeeds in most soils[]. Tolerates atmospheric pollution[].
A slow-growing tree[], it is growing well at the Hillier Arboretum in Hampshire (hardiness zone 7) where a tree was 7 metres tall and 8 metres wide in 1993[].
Trees have a light canopy, they come into leaf late in the spring and drop their leaves in early autumn[] making them an excellent top storey tree in a woodland garden.
Plants in this genus are notably resistant to honey fungus[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

We have no records of edibility for this species. The obliquely diamond-shaped seedpods are not pulpy inside, they are around 35mm long and 25mm wide, containing a solitary seed (rarely two), 10 - 15mm in diameter)[, ].

Medicinal

None known

Agroforestry Uses:

Trees have a light canopy, they come into leaf late in the spring and drop their leaves in early autumn[] making them an excellent top storey tree in a woodland garden[].
Having an extensive root system, the tree is planted for stabilizing wet banks and marshes[].
When planted close together and severely pruned, most Gleditsia species form good windbreaks and hedges. With their usually very spiny trunks and branches, the hedge becomes an effective barrier, and with its ability to fix atmospheric nitrogen, it also enriches the soil[, ].

Other Uses

The heartwood is light red to reddish brown; it is demarcated from the wide band of yellowish sapwood. Texture is moderately coarse, with a straight to irregular grain; there is no characteristic odour or taste; lustre is high. The wood is very heavy, very hard, tough, strong, durable in contact with the soil. It is not easy to work, but finishes smoothly. It is used primarily for making fence posts and rails, general construction, furniture, interior trim[, , , , ].

Propagation

Seed - pre-soak for 24 hours in warm water and then sow in spring in a greenhouse[]. The seed should have swollen up, in which case it can be sown, if it has not swollen then soak it for another 24 hours in warm water. If this does not work then file away some of the seed coat but be careful not to damage the embryo[]. Further soaking should then cause the seed to swell. One it has swollen, the seed should germinate within 2 - 4 weeks at 20°c. As soon as they are large enough to handle, prick the seedlings out into individual deep pots and plant them out into their permanent positions in the summer. Give the plants some protection from the cold for their first few winters outdoors.