Time Frame

• A deciduous azalea shrub in flower attracts a swallowtail butterfly.feeding butterflies image by Penny Williams from Fotolia.com
  
  According to the American Azalea Society, the bloom time for azaleas is widely variable, although many gardeners associate spring as the prime flowering season. Precise timing of flowering varies by azalea species as well as the garden's geography -- latitude and elevation and associated climate. Azalea shrubs tend to bloom all at once and the flower display lasts about two weeks. Any specific azalea shrub variety blooms earlier and the flowering season is more spread out in a mild climate such as the South, but it will be later and slightly shorter in the North. Some azaleas, such as those in the Encore series, bloom in spring and again in fall.
  
  

Flower Development

• Flower buds first form in summer and mature in fall.azalea bud image by hazel proudlove from Fotolia.com
  
  Typically, azaleas complete their flowering in spring to summer and then new growth matures in summer and fall. During the summer and fall months, next year's flower buds initially develop in tissues and then rest dormant until spring. The winter chill helps the plants time proper final development and swelling of buds that open in spring. Some azaleas bloom in summer on growth that first starts in spring. And those that rebloom in fall do so from growth that matures over summer.
  
  

The Issue of Pruning

• The more healthy branches and twigs an azalea bush has, the more potential for flowers. Thus, pruning is employed to shape or rejuvenate shrubs. Since flower buds are formed well in advance of flowering, pruning at the wrong time of year removes flower buds. The American Azalea Society says the best pruning time for azaleas is in early spring, even though this means removing flowers for later that spring. The second best time is during flowering. The third best time and the period most gardeners choose to prune their azaleas, is immediately after flowering occurs. Dead branches are pruned away any time of year and gardeners typically avoid pruning in fall since any ensuing growth doesn't mature in time to survive the first winter cold snaps.
  
  

Diminished Blooming

• Many factors lead to reduced production of flower buds.Azalea image by Denis Morgun from Fotolia.com
  
  Several factors lead to a reduced production of flowers on azaleas. Pruning, especially at inopportune times, is one factor. Excessive winter cold can dry out and kill flower buds. Less than three hours of direct sun each day also reduces the number of flowers. Lastly, soil conditions affect plant health and subsequent production of flowers. An acidic organic-rich soil that is evenly moist during the growing season is necessary. Phosphorus deficiency in the soil limits flower production, too.