Removing withered flowerheads is particularly recommended for young plants that have attained a height of 1 m (40 in). This prevents essential nutrients, which the shrub needs for growth, being wasted on the unnecessary formation of seeds. Deadheading also allows the young shoots, which form at the base of the flower stalks, more room to develop. The best time to deadhead flowers is immediately after flowering. Do this gently so that any young shoots that have begun to develop are not damaged or broken off along with the faded flowers.
Removing new shoots, or pinching out as it is usually called, will encourage open, sparsely growing rhododendron shrubs to develop denser, more compact growth, Simply pinch out any new shoots as they appear. This will activate the leaf along the sides of the branch and three or more young shoots per branch will develop instead.
Generally speaking, rhododendrons shouId not be pruned. There are, however, some exceptions. Pruning will be necessary if: