Tropical Plant Database - Plant Details

Hibiscus arnottianus subsp. immaculatus is a shrub or small tree generally 8 meters in height, though individuals may reach 10 meters tall. The leaves are oval with a smooth upper surface and smooth or slightly round-toothed edges. The leaves are 4 to 10 centimeters long and often have red veins and stems. The faintly fragrant flowers have white petals 8 to 11 cm long, 2.5 to 3.5 cm wide, with the calyx being 2.5 to 3 centimeters long. Anthers are arranged along the upper third of the white staminal column 10 to 14 cm long. This subspecies is distinguished from the other native Hawaiian members of its genus by its white petals and white staminal column. The flowers may be slightly pink or may age to pale pink. In cultivation, Hibiscus arnottianus blooms almost continuously.
(Wagner,W.L., Herbst,D.R., Sohmer,S.H. 1999. Manual of Flowering Plants of Hawai'i.)
(USFWS. 1996; Criley. 1998; Criley. 1999; Koob. 1998; Rauch. 1997)

The flower buds of the Koki'o ke'oke'o were used as a mild laxative by the early Hawaiians. Also, the fibers of this tree were used for cordage.

(Bornhorst, H.L. 1996. Growing native Hawaiian plants: A how-to guide for the gardener.)

Threats to Hibiscus arnottianus subsp. immaculatus include the destruction of habitat by feral goats and potential inbreeding resulting from a restricted genetic pool.

Current Management Summary:
The Nature Conservancy of Hawai'i is working with State and local hunters in remote sections of Kamakou and Pelekunu to try to reduce the population of feral goats.

NTBG propagated Hibiscus arnottianus subsp. immaculatus and plans to research propagation methods and feasibility of long-term seed storage (USFWS, 1996.)

NTBG currently has ex situ holdings of seeds in its seed bank and plants growing in the McBryde Garden representing one out of the four populations.

Research Management Needs:
1. Propagation and maintenance of ex situ genetic stock should be continued for Hibiscus arnottianus subsp. immaculatus.
2. Exclosures should be built for protection against feral goats.
3. Determine the best methods for ex situ propagation and transplanting. Also, a research program is recommended to study the growth and viability of Hibiscus arnottianus subsp. immaculatus.
4. Conduct pollination biology and reproductive studies.
5. Map genetic diversity in the surviving populations of Hibiscus arnottianus subsp. immaculatus.

Ex Situ Needs
1. Survey ex situ holdings and conduct molecular fingerprinting.
2. Establish secure ex situ stocks with full founder representation.
3. Develop proper horticultural and pest management protocols.
4. Propagation and maintenance of ex situ genetic stock should be continued.
(Recommendations derived from Chapin, M. H. and Maunder, M. USFWS. 1996.)

Hibiscus arnottianus subsp. immaculatus is extremely rare and grows in only a few valleys on Moloka'i Island, Hawaii.
(USFWS. 1996.)

Hibiscus arnottianus subsp. immaculatus found only in four populations on the Island of Moloka'i. It is considered to be the rarest of all of the Hibiscus species and is listed as an endangered species.
(Wagner, W.L.,Herbst, D.R., Sohmer, S.H. 1999. Manual of Flowering Plants of Hawai'i; USFWS, 1996.)

The gardeners and scientists of National Tropical Botanical Garden (NTBG) have successfully propagated Hibiscus arnottianus immaculatus.
No other conservation efforts have been undertaken as at this time.

We currently have 6 herbarium specimens for Hibiscus arnottianus subsp. immaculatus in our collection. Click on any specimen below to view the herbarium sheet data.

• 013557 - collected by K. R. Wood in 1990
• 025329 - collected by David H. Lorence in 1997
• 030053 - collected by Kana Watanabe in 2000
• 072601 - collected by Susan M. Deans in 2016
• Unassigned - collected by Susan M. Deans in 2016
• Unassigned - collected by David H. Lorence in 2020