It is endemic to Hawaii, where it is limited to Kauaʻi (Waimea Canyon) and Oʻahu (Waiʻanae and Koʻolau Ranges).

[4] Its common names include Āulu,[5] Oahu soapberry, alulu, kaulu, and lonomea.

The fruit is a shiny, leathery berry roughly 2 centimeters long, containing one large black seed.

[12] Early Hawaiians used the hard blackish seeds for medicinal purposes and to string permanent lei.

[16] Sapindus oahunesis are also important in providing habitat for native bird species, such as the ʻelepaio .

[19] The most common pests of the Sapindis oahunesis is the black twigboreers and false powderpost beeetles which bore into the wood.

Occasionally, whiteflies will infest the underside of the leaves, which may be treated with an at home insecticidal soap.