Hibiscus arnottianus is a shrub or small tree generally 4.5-6.0 metres in height though a few individuals will grow taller. These specimens can be up to 6 metres in diameter. Individual plants vary in appearance from open and airy to compact. The leaves are oval with a smooth upper surface and smooth or slightly toothed edges. The leaves are 10-15 cm long and often have red veins and stems.
The single white flowers are pinwheel shaped, up to 10 cm across, and borne at the ends of the branches. The staminal column is pink to red (except in subspecies immaculatus which has a white column). The flowers may be slightly pink or may age to pale pink, and are slightly fragrant, with a smell reminiscent of the fragrant cyclamen. In cultivation, Hibiscus arnottianus blooms almost continuously.
Hibiscus arnottianus is a Hawaiian endemic plant with one endangered subspecies. It is native to the moist to wet forests of the mountains of Moloka'i and O'ahu. Subspecies arnottianus grows at elevations of 120 to 760 metres in the Wai'anae and eastern Ko'olau mountains of O'ahu. Subspecies immaculatus is extremely rare and grows in a few valleys on Moloka'i. Subspecies punaluuensis grows in the Ko'olau Mountains at elevations of 200 to 670 metres. The shrub grows extremely well in Melbourne's climate.
This post is part of the Floral Friday Fotos meme.