Welcome to the Rhododendron GenomeIntegrative Explorer
The genus Rhododendron of the heather family (Ericaceae) is well known for the outstanding beauty and great diversity of corolla among its more than 1,000 species and 30,000 cultivars. Rhododendron simsii (Indoor azalea), an evergreen azalea of the subgenus Tsutsusi, is the most widely cultivated Rhododendron species. Within the last four centuries, an increasing number of azalea cultivars were artificially selected and developed from the diversity of wild relatives and natural hybrids. As the primary ancestors of azalea cultivars, R. simsii was introduced into Europe in the 18th century from China and its breeding for ornamental use began in England and well developed in Belgium. Then, R. simsii hybrids become one of the most important pot plants in Belgium, with an annual production of approximately 40 million pots. Although R. simsii naturally bloom in later spring to early summer, the easy-care and color-rich cultivars can bloom early at Christmas and Spring Festival when few flowers are available. Now azalea cultivars have become one of the most popular pot plants and landscape shrubs in Europe, North American, and Asia.