Certified GKH Gardening Expert
Do you have the big leaf type that blooms on old wood (buds form the previous summer)? If so and you had a late freeze, it would have zapped your buds. Some varieties bloom on old and new wood, so if you lose the first flush in spring, you get bloom in mid to late summer. The most reliable bloomers are the ones that bloom on new wood. So next time you buy hydrangeas be sure to purchase types like smooth or panicle hydrangeas.
Improper pruning is the next big reason. Here are more causes of no bloom and how to fix it: