Probably no other group of plants arouses as much devotional compliments and obsessional discouragement as the genus Rhododendron. Where they can be grown, few plants can fit their bewildering assortment of striking, profuse, commonly brilliant blossoms, remarkable form, and attractive leaf.
Rhododendron is an extensive genus, with more than 900 species and 10,000 varieties. Azalea is a string within the Rhododendron genus. There are deciduous and evergreen, small- and large-leafed, and dwarf and tall types of these plants. The range of colours is endless, including flowers that are bicolored and solid; some have a heady perfume. Depending on the variety and location, azaleas and rhododendrons bloom from late winter.
Botanists are still arguing over exactly what anatomical characteristics distinguish Azalea from Rhododendron. Most rhododendrons are evergreen, and while many azaleas are not evergreen, both azaleas and rhododendrons have deciduous and evergreen species. A common misconception is that azaleas are consistently smaller than rhododendrons in leaf and form, while in fact several rhododendrons are tiny, rock-garden with leaves smaller dwarfs. Sizes of both plants change from 8 to 80 inches.
There is, however, one significant difference be tween rhododendrons and azaleas — namely, where the buds are located. Rhododendron buds are consistently located just above the leaf rosette; under the bark along the whole branch, the buds are hidden on azaleas. This difference affects the sort of pruning each type demands.
The name of rhododendrons and azaleas as finicky, frustrating plants is misleading. If put in given suitable growing conditions and a favorable place, these plants are simple, care free, and long lived.