Species list


Gleditsia triacanthos

Honey locust

Honey locust, thorny locust (Eng), acacia de tres espinas, acacia de tres púas (Spa), acàcia de tres punxes (Cat), arkazia hiruarantza (Baq), espinheiro-da-Virgínia (Por).


DID YOU KNOW...? A substitute for carob pulp can be extracted from this tree’s fruits, which is used to thicken, give consistency to and stiffen jam, ice cream, cake, creams, toothpaste, soap, paper, and fabric.


This is a large, stocky tree that can be up to 40 m tall, with smooth, fissured grey bark. It often has long steely spines that develop in groups of three, with a thick central thorn and two finer, side spines, which is where its Latin name comes from. The leaves are deciduous, alternate, and 20-40 cm long. They are compound, comprising an even number of 8-20 leaflets or pinna (even-pinnate). These leaflets are oval, 1-3.5 cm long with slightly crenate or very finely toothed margins, so they may seem entire. The flowers are greenish and grouped in hanging strands. The fruits are large, showy legumes that often remain in the tree after the leaves have fallen. They are similar to those of the carob tree (Ceratonia siliqua L.), but are somewhat larger and narrower. They measure 20-40 cm long by 2.5-5 cm wide and are coffee brown in colour.


This is a fast-growing plant that is resistant to pollution, extreme climates and severe pruning. Many specimens are hollow because of abusive pollarding. Although it endures drought well, it is potentially a riparian species which grows much better in bright spots. When it becomes established in the wild it is associated with elms and poplars. It occurs naturally from sea level up to 600 m, even though in many places it is planted at higher altitudes.


It is native to central and eastern North America. It occurs across the Iberian Peninsula as an ornamental plant and has become established in the wild in many places. It is especially abundant along watercourses in Málaga, Murcia and Granada, and next to the Río Mondego, in La Coruña. It is included in the Atlas of invasive alien plants of Spain.