Family: Caesalpiniaceae
Common Name: Honey Locust

Native to North America and Asia, these hardy, deciduous trees, with their attractive, spread­ing, fern-like foliage, are useful as shade, street and park trees. Their main drawback is their rather vicious thorns.

Species

G. aquatica, swamp locust, zone 6, grows to 18 m (60 ft), with insignificant white flowers. The thorns are about 10 cm (4 in) long, but not as profuse as on other species.

G. japonica, zone 6, is a spiny tree, to 20 m (65 ft), with purplish branches when young and very long, twisted seed pods. G. sinensis, zone 5, from China, to 13 m (42 ft), has cylindrical, branched spines.

G. triacanthos, honey locust, zone 3, can reach to 30 m (100 ft), though seldom more than 15-20 m (50-65 ft) in culti­vation. It has an open canopy, the fine foliage colouring golden yellow in autumn, insignificant white flowers and long, twisted seed pods per­sisting throughout winter. The form inermis is a thornless, drought-resistant type. Cultivar 'Rubylace' has rich ruby red foliage and 'Sunburst' grows moderately slowly, with bright golden yellow foliage.

Cultivation

While preferring good quality soil, gleditsias can adapt to a variety of conditions. Propagate species from seed which should he soaked in hot water before planting. Cultivars with special features are generally grafted onto seedling understocks. Best where supplemen­tary irrigation is available, they will tolerate drought once well established. Many species are very hardy and will tolerate climates with very hard frosts.

Climate

There are species suited to various climatic zones.