The word "rhododendron" (stress on the single letter "e") consists of two Greek words: "rhodes" - a rose and "dendron" - a tree. At first, the oleander was called the "rose tree". Only in 1583 the name rhododendron was associated with a specific species - rusty rhododendron (Rhododendron ferrugineum), a native of the Alps. In 1753, K. Linnaeus named 9 species of rhododendrons - 3 evergreen and 6 deciduous, and the latter he attributed to the genus Azalea L. This division was later found to be incorrect; botanists classify deciduous and evergreens in open ground to the same genus - rhododendrons, and to azaleas - thermophilic indoor plants, indoor and greenhouse. But in the horticultural world practice, the name "azalea" has been preserved since the time of Linnaeus.
Currently, deciduous rhododendrons are called azaleas: Rhododendron occidentale (R. western), Rhododendron viscosum (R. glutinous), Rhododendron japonicum (R. Japanese) and their varieties, as well as the most popular group of hybrid azaleas Knap Hill (Nap Hill) and evergreen hybrids Rhododendron obtusum (R. blunt) - the so-called Japanese azaleas. The latter should not be confused with the deciduous Japanese rhododendron (Rhododendron japonicum) and its varieties that grow well in the Moscow region. Japanese azaleas (Japanische Azaleen) are semi-evergreen and evergreen low (30-60 cm) shrubs with a dense dense crown. They grow well in a quiet place protected from wind and midday sun, depending on the variety, they can withstand frosts from -20 to -27 ° C. The color scheme is varied: white, pink, purple, red. The difference between deciduous azaleas and evergreens is also conditional, since the latter can lose all leaves during a cold winter. Deciduous azaleas are less demanding. These are shrubs 1–1.5 m tall, with a lush crown, blooming from mid-May to mid-June. They are winter-hardy, grow in sunny places, and tolerate dry, hot weather more easily. Their color range is varied. It is better for beginners to purchase these particular plants.