Sapindus rarak, commonly known as lerak or klerek in Indonesia, is a deciduous tree native to a range of forest habitats in South and East Asia, including India, Sri Lanka, South China, Taiwan, and Indonesia. It can reach up to 138 feet in height, with a canopy that spreads widely, providing significant shade. This species is particularly adapted to tropical monsoon forests and lower montane forests, where it is a part of the diverse forest ecology. The tree is characterized by its large, pinnate compound leaves, which can be up to 20 inches long, and its small, white flowers that bloom in panicles. The fruits are spherical drupes that turn yellow to golden when ripe and contain saponins, which are natural surfactants.

Sapindus rarak is valued for its fruits, which are harvested to produce a natural soap that is gentle on fabrics and does not cause colors to fade, making it ideal for washing delicate textiles like batik. The tree is also used for its wood, although it is not highly durable. In cultivation, it requires a well-drained soil, moderate water, and full sun to part shade conditions. While not commonly grown in ornamental horticulture, it has potential for use in reforestation projects and as a source of eco-friendly soap. Gardeners should be aware that the tree can grow quite large, making it suitable only for spacious landscapes.CC BY-SA 4.0