I planted a Tardiva Hydrangea two years ago in a part-sun situation. Fed it with Miracle Gro (for acid-loving plants)... got ONE BLOOM on it last summer. I'm very disappointed. Anyone else ever had this problem?
Tardiva Hydrangea not blooming!
http://davesgarden.com/forums/f/tas/
try here maybe someone can help you with the specific variety as i never do anything to mine and they bloom just fine. hope this helps.