There are several reasons why hydrangeas fail to bloom. Improper pruning is the most common. Most mophead hydrangeas bloom on two year old wood. So if you prune back the green stems that did not flower they will not mature enough to from flower buds. Even if you don't prune at all (hydrangeas grow great with no pruning - just give them lots of room) then the failure to flower could be lack of morning sun. To bloom best hydrangeas need at least half day of sun. Finally, a cold spring or freezing winter will kill the immature flower buds and result in nice leaves but no blooms. There are some hydrangeas called "Mountain hydrangeas" (Hydrangea serrata) that were bred to flower in cold winter areas. One variety from Proven Winners is called "Tuff Stuff" and comes in red and a blue form. Hope this helps, let us know if you get flowers next summer. Keep growing, Marianne Binetti