Rhododendron is a genus of about 700 species of flowering plants native to temperate regions of the Northern Hemisphere, Asia, and Australia. The flowers are typically in large, showy clusters. Azaleas are native to temperate regions of the Northern Hemisphere, from Canada to northern China, and are classified into three groups based on leaf shape.
Rhododendrons and azaleas are popular garden plants worldwide. The Rhododendron Society of America (RSO) is an international society for the promotion of the horticultural use of rhododendrons and azaleas. The rhododendron has been used in traditional Chinese medicine. Etymology The word rhododendron comes from two Greek words:
rho, meaning "rose", and dendra, meaning "tree". The leaves are deciduous and the plant bears flowers that bloom in early spring. The genus was named by Carl Linnaeus in 1753 as a combination of the Greek words rho, meaning "rose", and dendron, meaning "tree". Rhododendrons are among the most popular plants for gardens worldwide, and they are used in parks and conservatories. They are also grown as street trees. Rhododendrons were once thought to be hardy only in the north temperate regions, but now can be found growing successfully in subtropical climates as well.