Considerations

• It is important to determine which type of hydrangea you are growing. Some species, such as H. arborescens, bloom on new wood so pruning at the wrong time may prohibit the hydrangea from blooming. If you have any doubt as to which variety you are growing, contact your county University of Illinois cooperative extension office.
  
  

Timing

• Mophead hydrangeas don't require pruning. Prune lacecaps in the summer, any time before August. Prune H. arborescens in the early fall in Illinois and prune H. paniculata anytime but summer. Finally, climbing hydrangea can be pruned anytime but spring.
  
  

Warning

• When pruning more than one hydrangea plant, sterilize your pruning equipment before moving from shrub to shrub. This will avoid spreading any disease that you didn't notice while pruning.