Azaleas should be pruned in early spring or when their flowers are already in full bloom. Flowering azalea shrubs must be pruned periodically so the plant has room for new growth, but improper pruning could make the plant grow wildly or damage it and prevent future flowering. Knowing where to cut when pruning azalea is important to maintaining the plant's health.
Azalea pruning begins with shaded branches that have little hope of seeing sunlight. Branches that are deeply shaded are likely to die out and become old wood, so they're best removed first. Cut shaded branches back to the main trunk or stem, if possible. Otherwise, simply remove the shaded area of the branch, or as much of the branch as can be reached with pruning shears.
Dead growth and old growth must be removed from the azalea. Tall branches may grow up out of the shrub, making the plant look unkempt. Cut all dead branches away, and remove two to three of the tall branches growing out of the top of the shrub. Cut tall branches back to a juncture where another branch has begun to grow. Roughly two-thirds of the old branch should be cut away. Gently nick dead branches with a fingernail until green wood is exposed, and cut the dead branch back to this point.
Azaleas grow heartily and may threaten to overrun garden beds, decks and driveways. Pruning helps azaleas maintain an attractive shape and size. Identify long branches and areas of the shrub that are showing signs of too much growth. Cut the ends of branches back to the juncture where other branches are growing, reaching into the shrub to complete the task. Do not be afraid to cut deeply into the bush; pruning stimulates new growth that will cover holes.
Shoots and Suckers
Small suckers may appear around the base of azalea plants.The suckers are likely to be shaded by the rest of the plant, so prune them as they appear. With young azaleas, it's best to leave at least three of the suckers so new main branches may form. If azaleas look too thin, pinch away the young shoots to encourage dense growth. Shoots should be brittle to the touch, hard enough to snap when bent in two. Pinch shoots in the height of summer, during June or July. Do not prune too late in the season, as no new growth will be produced.