Hibiscus arnottianus (Hawaiian White Hibiscus) is an evergreen shrub or small tree that grows 5 to 10 feet tall and wide, although some specimens may reach up to 20 feet tall. It does best in full sun or semi-shade, with slightly acidic, well-drained soil. Water regularly, but avoid over-watering. Fertilize in the early spring with a balanced fertilizer. Prune to shape after flowering.
In USDA hardiness zone 9-11, Hibiscus arnottianus may be grown in pots and brought in during winter months. In order to survive in cold environment, it is ideal to locate it in a sheltered area such as a patio or under a tree. The pot should have some drainage holes in it and should be filled with a well-draining soil mix. Additionally, keep in mind that Hibiscus arnottianus is a tropical plant, it won't survive freezing.
Hibiscus arnottianus is a endangered Hawaiian endemic plant. It is native to the moist to wet forests of the mountains of Moloka'i and O'ahu.