Answer: The most common reasons for hydrangeas not to bloom are excessive winter cold damage and pruning at the wrong time. The bigleaf hydrangeas (Hydrangea macrophylla) bloom on old wood that grew the previous year. If winter kills back the branches, then it will not be able to bloom the next summer. Also, the only time to prune these is right after they bloom. Pruning at other times will remove the flowering wood for the next season. I hope this helps you trouble shoot.
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