A Rhododendron By Any Other Name...
Azaleas are flowering shrubs making up part of the genus Rhododendron. Originally azaleas were classed as a different genus of plant, but now they are recognised as two of the eight sub-genera of rhododendrons - subgenus Pentanthera typified by Rhododendron nudiflorum and subgenus Tsutsusi typified by Rhododendron tsutsusi.
There are deciduous azaleas, and evergreen azaleas. One of the major differences between azaleas and the rest of the rhododendron family is their size. Another is their flower growth. Rhododendrons grow their flowers in clusters, while most azaleas have terminal blooms (one flower per flower stem). However, they have so many stems that during the flowering season they are a solid mass of colour. Azaleas are recognised by these flowers blooming all at once, in a showy display for a month or two in spring. The exception to this rule is a small group of azaleas which grow their flowers in tight terminal clusters that look like little balls of colour.
Plant enthusiasts have created hybrid azaleas for hundreds of years. This human genetic modification has produced over 10,000 different cultivars which are propagated by cuttings. Azalea seeds can also be collected and germinated.
Azaleas should be grown in well-drained garden soil or in pots, in a cool, shady position. Fertilizer is optional, although some species do need regular pruning.
So azaleas are rhododendrons (not the other way around though). Got it. Now that makes much more sense!