High Quality Content by WIKIPEDIA articles! This List of Rhododendron species includes species of the genus Rhododendron, which is in the plant family Ericaceae. Depending on the source, there are anywhere from 800 to over 1,100 wild species. The vast majority of Rhododendron species are native to the eastern Himalaya and southeast Tibet, along with the islands of Java, Sumatra, Borneo, New Guinea, and the Philippines. The rest are broadly spread throughout the northern hemisphere in relatively small isolated populations, including Japan, northwestern North America, the Appalachian, and the Caucasus Mountains.