Hello, chocrnmom_2010. Some people in Zone 5 have experienced this sort of problem and now some plant nurseries are rating its winter hardiness starting at Zone 6 instead of Zone 5. I am wondering if this is what is causing the problem. If you wish to experiment, apply winter protection techniques this winter and see if blooms next year.

Other suggestions... do not fertilize it in or after July in order to make sure it goes dormant. This will prevent flower buds from getting zapped if temperatures drop a lot while the shrub is still in growing mode. If you prune, do not prune after the flower buds have started to develop; that is sometime around now (July-August). Do not use fertilizers high in nitrogen. Make sure lawn fertilizer pellets do not land in large numbers under the hydrangea either. Compost, manure and cottonseed meal will be fine once a year in June.

Lemon Dadddy are only root hardy to zone 5. Sometimes even in bad winters in zone 6 they will not bloom. You will have to winter protect to get blooms. I have tied up the canes, double burlapped and stuff with leaves and do pretty good. If you want a macrophylla hydrangea that doesn't require winter protection look at the Let's Dance or Endless Summer series.