Answer: There are only a few reasons for hydrangeas not to bloom and I think you've covered most of them: sufficient sunlight (4 hours of morning sun is best): pruning - perhaps at the wrong time. Most garden hydrangeas flower on new shoots which develop on old wood. If your hydrangeas typically freeze down to ground level each winter, or if you drastically prune in early spring, there may be no old wood from which new flowering shoots can develop. As a result you'll have lots of lush, green growth but no flowers. I would snip off a branch with leaves and take it into the garden center to be identified. You may well have hydrangea macrophylla (big leaf hydrangea) which will probably never bloom for you. A better choice for your area is a hydrangea such as Endless Summer which blooms on both old and new wood. This type will flower whether or not it freezes down to ground level each year or is pruned way back each spring.
Best wishes with your garden!
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