The kiawe is a spreading bush or moderately sized tree, bearing spines, spikes of greenish-yellow flowers, and long pods filled with small brown seeds.

It is a successful invasive species due to its ability to reproduce in two ways: production of large numbers of easily dispersed seeds, and suckering to create thick monotypic stands that shade out nearby competing plants.

The first kiawe was planted in Hawaii in 1828;[2] today it is a ubiquitous shade tree and invasive weed on the Hawaiian Islands, but provides firewood for heating and cooking.

[5] The clearing of kiawe (huarango) has been suggested as a major reason for the collapse of the Nazca culture in southern Peru at the beginning of the 6th century AD after an El Niño event led to flooding, erosion and desertification.

[6] Ecologists consider the huarango important to the ecosystem of the desert area west of the Andes in southern Peru, because of its ability to bind moisture and counter erosion.