Experts and BHG readers answer.
Well hydrangeas generally don't bloom for the following reasons. 1. Not enough sun. These plants require a fairly sunny spot (at least 6 to 8 hours a day). 2. They are being overfed. If you fertilize a hydrangea too much they can grow foliage, but no flowers. 3. Improper pruning. If you prune at any time, other than right after the flowers fade (or mid-summer if you had flowers) you'll be removing flower buds for next year's bloom. Do not prune at other times. 4. And finally, it may be that your hydrangea is the wrong variety for your region. YOu don't say what variety you have (they come in dozens of varieties) but in the north there are varieties that are hardy, but not hardy enough to flower because their flower buds freeze during the winter. I don't know what variety of hydrangea you have so it's hard to know exactly what's going on.