There are different types of hydrangeas. Some flower on second year growth and some on new growth. You’ll need to determine what type you have. If you have been cutting back your hydrangea every fall then you might have been cutting off the shoots that will flower the following summer. Heree’s a wonderful site that will help you identify which type of hydrangea you have and when it should be pruned. http://www.hydrangeashydrangeas.com/pruning.html