Lemonyellow Rosemallow Hibiscus calyphyllus

Hibiscus calyphyllus, the lemonyellow rosemallow, is a shrub from tropical Africa belonging to the genus Hibiscus. In 1883 this Hibiscus was offered for sale in England under the name Hibiscus chrysanthus with Port Natal, Cape Colony, identified as the source. By 1891 the same Hibiscus was identified as Hibiscus chrysantha in the United States, a practice which may have continued into the 1930s and contributed to incorrect species identification. In 1892 the name Hibiscus calycinus was designated as the correct name for the species; but, by 1894 the currently accepted name Hibiscus calyphyllus is found in association with Hibiscus calycinus. At the beginning of the 20th century, this Hibiscus was sold as seeds in the United States under the name Hibiscus Giant Yellow. Because of the similarity of the flowers, it is quite common to find Abelmoschus manihot confused with Hibiscus calyphyllus in the early 20th century gardening literature of the United States, particularly in the area of cold tolerance. If the species identification is correct, the 1903 report in The Flower Garden states that: "Giant Yellow is a beautiful canary yellow with crimson throat, hardy as far north as St. Louis, but safer in the cellar above that latitude", then Hibiscus calyphyllus may have some degree of cold tolerance. St. Louis, Missouri is in USDA Zone 6a but there are currently no reports of Hibiscus calyphyllus overwintering in USDA Zone 6a; it is known to overwinter successfully in USDA Zone 8a. Wikipedia →