San Marcos Growers LogoSan Marcos Growers
New User
Wholesale Login
Enter Password
Home Products Purchase Gardens About Us Resources Contact Us
Nursery Closure
Search Utilities
Plant Database
Search Plant Name
Detail Search Avanced Search Go Button
Search by size, origins,
details, cultural needs
Website Search Search Website GO button
Search for any word
Site Map
Retail Locator
Plant Listings

PLANT TYPE
PLANT GEOGRAPHY
PLANT INDEX
ALL PLANT LIST
PLANT IMAGE INDEX
PLANT INTROS
SPECIALTY CROPS
NEW  2026 PLANTS

LIVE AVAILABILITY
  for MAY


Natives at San Marcos Growers
Succulents at San Marcos Growers
 Weather Station

 
Products > Hibiscus clayi
 
Hibiscus clayi - Red Kauai Rosemallow
   
Image of Hibiscus clayi
 
Habit and Cultural Information
Category: Shrub
Family: Malvaceae (w/Bombacaceae & Sterculeacea)
Origin: Pacific Islands
Evergreen: Yes
Flower Color: Red
Bloomtime: Spring/Fall
Synonyms: [Hibiscus newhousei]
Height: 10-16 feet
Width: 4-6 feet
Exposure: Full Sun
Irrigation (H2O Info): Medium Water Needs
Winter Hardiness: 30-32° F
Hibiscus clayi (Red Kaua?i Rosemallow) - A long lived tall, dense and upright shrub or small tree to 10 to 15 feet tall with smooth edged shiny green leaves. This plant produces its showy dark red flowers with 2 to 2 ½ inch wide flaring petals that are held near the ends of the branches year round in in its native Hawaiian islands but tends to bloom here in Santa Barbara spring through fall with peak in early summer (June & July).

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 clayi was once more widespread on the island of Kaua?i in the Hawaiian Islands but because of cattle and wild pig grazing, as well as habitat loss, it is now restricted to a few of the drier forests of eastern Kauai north of Kapa'a. It is federally listed as an Endangered Species and is listed as Critically Endangered on the IUCN Red List. The naming and conservation of this plant make for an interesting story. In 1928, Albert W. Duvel discovered several small hibiscus trees on Kauai that had been damaged by cattle. Duvel had a landscaping business and he essentially rescued the plants by bringing them into cultivation. The plant was later determined to be a new species that Isa and Otto Degener first named in 1959 in their Flora Hawaiiensis (AKA New Illustrated Hawaiian Flora) with the name honoring Horace F. Clay, a horticulturalist and instructor of botany at Leeward Community College on O?ahu. Margaret James Roe, in her study of the genus Hibiscus in Hawaii, named Hibiscus newhousei as another species from Kauai, but the currently accepted treatment is that H. newhousei is a synonym of H. clayi. The name for the genus comes from 'hibiscos' ,the Greek name for mallow. It is commonly called Red Kaua?i Rosemallow or Clay's Hibiscus but its Hawaiian name is Koki?o ?ula with "ula" meaning red. With its abundance of year-round flowers available, these flowers are often found in beautiful leis. We also grow another endemic Kauai hibiscus from the island of Kauai, the orange flowering Hibiscus saintjohnianus.

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

Information displayed on this page about Hibiscus clayi is based on our research conducted about this plant in our nursery library as well as from information provided by reliable online resources. We also include our own observations made about it as it has grown in the nursery gardens and other gardens visited, as well how the crops of this plant performed in the containers in our nursery field. We will also include comments received from others and welcome hearing from anyone who has information about this plant, particularly if it includes cultural information aiding others to better grow it.

 
San Marcos Growers closed for regular business at the end of 2025 as the property is being developed for affordable housing.
While our gates remain closed, we will open them by appointment so we can liquidate remaining plants, supplies and equipment. The plants remaining in the field are listed on our Live Inventory Page.