This noxious, spiny shrub reaches heights of 2 m. It forms impenetrable, monotypic thickets. The seeds are forcibly ejected up to 3 m from the parent plant. Long-distance dispersal is effected by man or by capsules attached to branches entangled in mammal pelage. Although much of the aerial portion of the plant may be destroyed by fire, the remaining portions regenerate rapidly.
Fire also aids in breaking the dormancy of the seeds.
It grows in mesic habitats between 200-2,100 m on Maui and Hawai'i. The infestations at Olinda, Maui and Humulula, Hawai'i are a considerable problem and beyond economically feasible mechanical or chemical control.