Pruning rhododendrons:
Timing is important! Right after it is done blooming, remove spent flower clusters as this will increase next year’s flowers. Then remove any broken, dead or very weak branches back to a main branch. Next, stand back and look at the shape of the plant and remove any erratic branches back to a main branch to improve the shape of the plant. On old or very dense rhododendrons, some branches can be removed to open the structure of the plant.