The azalea family consists of both evergreen and deciduous shrubs of varying cold hardiness. In winter, the combination of the sun and cold wind causes damage to most azaleas, including dieback and bark splitting. This can reduce the vigor of the shrub and make it more susceptible to disease during the growing season. Properly caring for these plants during the winter will help reduce injury.
Stop fertilizing by July 15. Any extra nitrogen after this point will promote new shoots of growth. These young shoots are especially susceptible to cold injury and would die in the winter climate.
Refrain from watering from September into the fall. This will help harden off the azaleas for the winter. If the fall is excessively dry, give the azaleas a good watering after the first killing frost. This will provide water for the plant over the winter and will not reduce hardiness. The ground should be wet before the cold weather sets in.
Place a thick layer of organic mulch around the base of the plant in late fall. Azaleas have shallow roots that need protection from the cold fluctuations and hard freezes. Keep the mulch from touching the trunk of the shrub.