Prune azaleas and rhododendrons right after bloom
Azaleas and Rhododendrons set new flower buds for next spring starting in mid to late summer. By pruning soon, you will have maximum bloom next year. You have probably noticed plants with sparse or one sided bloom that were pruned too late last year. Rhododendrons and azaleas should never be pruned with shears or power clippers. This causes unnatural thick growth and ruins the natural shape of the plants.
I am often asked if it is necessary to remove old dead flowers from rhododendrons and azaleas. It does improve plant appearance, but it makes no difference to plant growth. After a month or so the old flowers are covered by new vegetative growth.