Calliandra calothyrsus is a small leguminous tree or large shrub in the family Fabaceae. It is native to the tropics of Central America where its typical habitat is wet tropical forests or seasonally dry forests with a dry season of four to seven months, when it may become deciduous. This tree grows to about and has pinnate compound leaves and flowers with a boss of prominent reddish-purple stamens. It is not very drought-tolerant, and the above-ground parts can be short-lived in case of severe drought lasting many months, but the roots regularly resprout.
It is a multipurpose legume tree that can improve the soil by fixing nitrogen from the atmosphere. It is easily grown from seed; growth is slow at first but speeds up after the first year. It is used for reforestation, provides soil stabilisation on sloping sites, and provides useful high-quality fodder for livestock. It can be regularly coppiced to provide firewood. Because of these features, it has been planted in other parts of the tropics, but care may have to be taken so that it does not become an invasive species. However, it is not having many features of typical invasive trees and naturally grows in disturbed areas, not maturing forests.
Basic information
Calliandra calothyrsus is a small tree or a large shrub. It is usually 4–6 m high but might reach a height of 12 m under favourable conditions. The stems are quite small with a maximum base diameter of about 30 cm, the bark is blackish-brown. The canopy is dense with alternate, petiolate, bipinnately compound leaves of 10–28 cm lengths, which are folding together at night. Calliandra calothyrsus has both superficial and deep-growing roots. While the above-ground parts are only short-lived, the roots are able to sprout for up to 20 years.
The flowers are subterminal inflorescences with numerous long, hair-like purple or red stamens. Flowering starts 3–6 months after planting. The fruits consist of pods (8–11 cm long and 12 mm wide) that contain 3-15 seeds. Seeds mature 2 months after pollination and can be planted immediately as they have no dormancy period.
Systematics
The genus Calliandra belongs to the family Fabaceae (Leguminosae), subfamily Mimosoideae and tribe Ingae. Calliandra is a large genus with about 145 species, mainly from South and North America but also from Madagascar, India and Africa. Calliandra calothyrsus is one of seven species in a subgroup of the genus, the Racemose. Calliandra calothyrsus was described by Meissner (1848). The names Calliandra confusa and Calliandra similis can be used synonymously.
Origin and regions of cultivation
Calliandra callothyrsus is native to the humid and sub-humid areas of Central America and Mexico. There it can be found from the western Pacific coast of Mexico to Panama. But people most probably haven’t been cultivating or studying it there. Calliandra has been introduced to Java in 1936 and spread from there over the Indonesian Archipelago and to other parts of southeast Asia. Nowadays it can also be found in other parts of the tropics, mainly in Uganda, Rwanda and other parts of east Africa as well as in Australia, Hawaii, Brazil and Bolivia.
Environmental requirements
Temperature and altitude
Calliandra calothyrsus grows in regions with mean monthly minimum temperatures of 18-24 °C and mean monthly maximum temperatures of 24-28 °C. It can be found in a wide range of altitudes but seems to grow best at altitudes of 250–1300 m asl. However it can naturally reach an altitude of 1800 m asl in Guatemala and even grows well if planted at 2000 m asl as it was done in Indonesia and Kenya. At these altitudes Calliandra calothyrsus has quite some cool tolerance for a tropical species but it is not tolerant to frost.
Precipitation
Calliandra calothyrsus tolerates annual rainfalls of 700–4000 mm. It usually grows in wet tropical forests or in seasonally dry forests with a dry season of 4–6 months. Calliandra calothyrsus is not very drought tolerant and will die back under severe droughts. However, it is recovering in most cases after the onset of the rainy season. Calliandra calothyrsus is semi-deciduous in regions with long dry seasons whereas it is evergreen in humid climates.
Soil
Calliandra calothyrsus is adapted to different types of soils and more tolerant to depleted, low-phosphorus, acidic soils than other fast-growing fodder tree legumes. The best growing conditions are on light textured, slightly acidic soils but it is also well adapted to acidic soils with poor soil fertility and is able to grow on infertile and compacted soils.