Bloom sizes vary greatly on different varieties of azaleas. Compare the half-inch blossom on R. serpyllifolium with the 4 to 5 inch blooms on 'Higasa'. Petal edges may be flat, recurved, wavy or ruffled. Plant habits of the different varieties range from stiffly upright, to broad spreading, to irregular. Plant height can range from under a foot to well over 15 feet.
Many varieties are dense and compact, others are quite open, and some almost tree-like.
Most azalea varieties bloom in the spring, around May in the mid-Atlantic area of the United States, with some blooming a month or so earlier, and some as late as August. Blooms typically last for one or two weeks. In warm climates such as the deep south, some azalea varieties bloom again in the fall. Use find azaleas to make lists of the azaleas with the characteristics you like, and to see their details, including sources. While more sun typically produces more compact plants with more blooms, the blooms will not last as long.