Hawaiian cotton tree (Kokia drynarioides) is a native small tree that should not be confused with the larger tropical (non-native) plants known as silk cotton trees (Ceiba spp.) that are growing in Hawaiian landscapes. The red flowers of the Hawaiian cotton tree are pollinated by nectar-drinking birds with a naturally curving beak, such as the Hawaiian honeyeater, now extinct. Years ago, botanists collected seeds of the plant, added and grew them as part of the living collections in tropical conservatories around the world as well as within Hawaii, such as at the Waimea Arboretum.
A member of the hibiscus family, Malvaceae, Hawaiian cotton tree is identified in older literature by former scientific names like Gossypium drynarioides, Hibiscus drynarioides or Kokia rockii, according to the U.S. National Tropical Botanical Garden. These names remain valid synonyms but are no longer used by modern taxonomists, who use the scientific name Kokia drynarioides. Native Hawaiian names for this plant include "hau hele `ula" and "koki'o."
Hawaiian cotton tree is endemic (native only to) the main island of Hawaii. Naturally it grows on the leeward side of the island, such as on North Kona. Cotton tree grows in dry forests found on coarse lava covered with a thin, nutrient-depleted soil that drains quickly at elevations roughly 150 to 2,800 feet.
As of 2010, fewer than six Hawaiian cotton tree plants grow wildly on the Big Island. Although conservation efforts find more trees being grown on other islands, it remains a rare native plant. In fact, the U.S. National Tropical Botanical Garden reports that only five trees exist in the wild in the North Kona region. According to the state of Hawaii, Hawaiian cotton tree is listed as a federally endangered species, given the Hawaii Natural Heritage ranking of critically imperiled (G1), and holds the International Union for Conservation of Nature Red List status of critically endangered (CR D). Wild populations of this tree are threatened by livestock overgrazing, invasive weed species competition, forest fires and lava flows, and expanding human development into its natural habitat.
Hawaiian cotton tree grows to a mature height of about 25 feet with an open canopy of branches and foliage. The plump star-like green leaves have seven to nine lobes with reddish veins and a leaf base that looks heart-shaped. The scarlet-red flowers appear among the leaves at the tips of branches and resemble hibiscus flowers and produce huge amounts of nectar. The floral tube is long and curved. According to the U.S. National Botanical Garden, even the leaf veins can exude droplets of the nectar. Each flower is protected by three red bracts (known botanically as the calyx) and persist after the red petals drop away and the fruit capsule matures. The dry seed capsules contains five seeds.
Traditionally, native Hawaiians harvested the nectar and sap of the cotton tree to create a red dye used to color fish nets. Today, plants are grown as a specimen large shrub to small tree in nutrient-poor soils in tropical gardens across Hawaii and the fuzzy dry seeds are ornamental, according to Heidi Leianuenue Bornhorst, author of "Growing Native Hawaiian Plants."