United Kingdom 
how do we encourage our Hydrangeas to produce flowers, the ones we have are all healthy leaves, and so far no flowers
11 Jul, 2010
Answers
Other cause of non flowering is planting too near the root systems of other large shrubs and particularly trees - dryness at the roots means no flowers, and near other large plants is a very dry place to be.
12 Jul, 2010
did you prune them ? if you cut them back at the wrong time you may have inadvertently removed the flowers as they flower on last years wood , or another possibility is that the ends of the branches got caught by the frost
11 Jul, 2010