Pruning Time Line

• If you do opt to prune your rhododendrons, you can do so at any time during the year, according to Clemson University Extension. However, some times of year may be better than other. The American Rhododendron Society suggests that rhododendrons be pruned in early spring, before the new growth begins for the season.
  
  

Benefits of Spring Pruning

• Pruning rhododendrons in spring means you will not interrupt the plant's normal growth cycle. This means the shrub's buds will set as they normally do and you should see no difference in how your rhododendron blooms over previous seasons.
  
  

Deadheading

• Although trimming and pruning a rhododendron is not necessary each year, you should deadhead the shrubs. This involves breaking the trusses from the already spent flowers to stop seeds from forming. If seeds do develop, they will use a lot of the plant's energy any may affect flowering in subsequent seasons.
  
  

Disbudding

• Another form of regular maintenance that can help your rhododendrons is disbudding. To disbud your shrubs, you need to pinch the terminal buds on each new branch the plant has produced. This, in turn, causes the shrub to produce side shoots. You can disbud the shrubs in the spring, when the new growth occurs, and then again in the fall.