Answer: The most common reasons for lack of bloom on Hydrangea macrophylla are overly cold winters, pruning at the wrong time, and lack of light. According to your zip code you are gardening in zone 5A, the coldest part of zone 5. Although many hydrangeas will be root hardy for you, they will not be bud or stem hardy. Since these plants bloom on old wood that grew the year before, any winter damage reduces flowering. I suspect this is what has been happening to your plant. YOur local professional nursery staff may be able to help you troubleshoot also.
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