Cold Hardiness

• Most azaleas are hardy between U.S. Department of Agriculture Plant Hardiness Zones 5 through 7, but a few are hardy as far north as Zone 3. Deciduous azaleas are hardier than evergreen varieties, and native species are hardier than those brought from Asia. If you live in an area with cold winters, cold hardiness is a major concern. Swamp azalea and pinxterbloom are hardy to Zone 3. Pink-shell azalea, flame azalea and sweet azalea are hardy to Zones 4 or 5.
  
  

Size

• Azaleas vary in size, so consider your growing space and choose accordingly. For small spaces, try torch azaleas, Gable hybrids or Kurume hybrids, which grow 3 to 6 feet high. Pink pearl and Girard hot shot have bushy, low-lying growth. For tall plants that grow 12 feet or more, select a plant from the Exbury or Knap Hill hybrid collection.
  
  

Leaf Form

• Next to flowering, the evergreen leaves of many azaleas are their chief attribute. Evergreen azaleas grow best in mild climates, in a protected, partially-shaded location. They suffer sun scorch when placed on bright, dry sites. Some of the best evergreen azaleas are Kurume hybrids, such as coral bells, Hino-crimson, snow or Hinodegiri. On the other hand, if you live in an area where deciduous azaleas fare better, select one that offers attractive fall foliage, such as flame azalea, royal azalea or spicy lights.
  
  

Flowers

• Azaleas come in many colors, and the flower forms vary, from single-petaled plants to double or hose-in-hose blossoms that may have a strap-like, star or spider shape. When selecting azaleas, choose a color scheme that complements your home and the surrounding greenery. Many azaleas have vivid hues that may clash with softer landscaping elements. If planting several azaleas, choose one color or two complementary shades. Avoid planting azaleas with colors that clash together, such as bright pink and bright orange.