Plant in full sun with regular garden water. It is hardy to a light frost but best in coastal near frost free gardens. This is a nice garden plant or it can be kept as a container specimen.

Hibiscus saintjohnianus comes from a small area between 500 and 3,000 feet in elevation on the northwest side of the island of Kauai in the Hawaiian Islands, where it grows in moist forests, cliffs and canyon slopes. It was known as Hibiscus saintjohnianus or Hibiscus roetae, but was reclassified as a subspecies of Hibiscus kokio with the subspecies kokio differing by having hairy leaves and stems, long bracts on the calyx, and red flowers. The subspecies kokio is known to grow on the islands of Kauai, Oahu, Molokai, Maui and possibly Hawaii while the subspecies saintjohnianus is native only to northwestern Kauai. DNA evidence has supported the evidence to elevate Hibiscus kokio ssp. saintjohnianus back to full species status as Hibiscus saintjohnianus, though some botanical databases still list it as a subspecies of Hibiscus kokio.

We also grow another endemic Kauai hibiscus, the red flowering Hibiscus clayi. The name for the genus comes from 'hibiscos' ,the Greek name for mallow. and the specific epithet honors, Dr. Harold St. John (1892-19991), a professor of botany at the University of Hawaii and one of Hawaii's most well known botanists. The St. John Plant Science Laboratory building on the Manoa campus of the University of Hawaii, which houses the botany department, is named after him. The previous specific epithet comes from koki?o, the Hawaiian language name for the native hibiscus. Other common names for this plant include St. John's Hibiscus, St. John's Rosemallow, Koki'o, Koki'o 'ula , Koki'o 'ula'ula and Maku.

We thank our salesman Matthew Roberts for sharing the cuttings of this plant from his Santa Barbara garden with us. 

The information about Hibiscus saintjohnianus that is displayed on this web page is based on research conducted in our nursery's horticultural library and from reliable online resources. We will also include observations made about this plant as it grows in our nursery gardens and other gardens that we have visited, as well how the crops have performed in containers in our nursery field. We also incorporate comments that we receive from others and welcome hearing from anyone with additional information, particularly if they share cultural information that aids others growing this plant.