Samanea saman aka Cow Tamarind

Samanea saman, or rain tree, belongs to the pea family, Fabaceae. Some garden sources call it Albizia saman. Its native range spans Central America and northern South America. Kew places its southern limits in Venezuela and Ecuador. It grows in grassland, dry forest, and moist woodland edges. People have planted it across the tropics, where it has also naturalized.

This fast-growing tree needs room for its broad, low crown. Garden trees reach 50–80 feet [15–24.4 metres] tall. Their crowns can span 100 feet [30.5 metres]. Other accounts give heights of 98 feet [30 metres]. Rare trees reach 197 feet [60 metres]. The short trunk often bends and can grow thick. Its bipinnate leaves have many small leaflets. These fold at night and during rain or cloudy weather. Trees stay green in humid sites but may shed leaves during drought.

The showy pink flowers add colour above the shade. Bees and butterflies or moths pollinate the blooms. The pods have thick edges and hold sweet, sticky brown pulp. People eat this pulp and use it to make drinks. Useful Tropical Plants lists no known hazards for this species. This does not establish that every plant part is safe. The same source records folk uses for bark, leaves, fruit, and seeds. These records do not establish that those treatments work.

Grow rain tree in full sun for the best flowering. It accepts light shade and needs soil that drains well. Average soil with moderate moisture suits it. It withstands some drought, but regular water supports better growth. High summer heat suits the tree, while frost can harm it. Missouri Botanical Garden lists USDA zones 10–11. It gives a minimum temperature of 35–40°F. The tree can grow from seed, and growers also use cuttings.

Its wide crown gives shade in parks, pastures, and large gardens. People also plant it along roads and over crops. Its size makes it a poor fit for small spaces. The wood has uses as timber and takes a fine polish. The bark supplies gums and resins, including gum used as glue. Wilt has become a serious problem in some regions. Mimosa webworm can also attack the tree. Fallen seeds may produce many young trees beneath the crown. Avoid planting where wilt already causes trouble, and allow space for its full spread.