I had that same problem. I posted here, this is many year ago. I was told I had a wild hydrangea. I called wayside. It was two years planted, no blooms and then blooms so small that they are insignificant. So, they sent me a new plant, but then by chance the angel of the sprinklers was altered. The plant began to get much more water, and then it bloomed fine. I then had two plants. Huge blooms like dinner plates, but the second plant, I had squeezed into in area with little room. I tried to take out a small tree, but then it grew back. The second plant took to sagging with the flowers, they were on the ground. So, I removed the second hydrangea and let the small tree grow back. Then we had a cold day last Dec. and the first one died, or at least refused to come back, and I found fuchsia, I wanted to add. Long story, but the heart of it is, I should have tried more water before writing off the first plant.

Here is a link that might be useful: Photo of the dinner plate size blooms

I should have been more specific in my original post. I have never fertilized the shrub. Will adding fertilizer now do anything to promote more blooms this summer?

My Annabelles are nearly 10 years old--and I have never fertilized them. They bloom their heads off with no help beyond plentiful water.

Water, not fertilizer, makes the difference on mine.

Kate

Thanks for the replies. I just went out and placed a soaker hose around my annabelle to see if more water might help.

I had the same problem where my annabelles did not bloom 3 years running. they would start to bllom but then never fully develop and would look like a flat lacecap with only a few flowers opened. People told me I probably got jipped with a wild hydrangea so I returned them. They were planted in the shade beneath a river birch, so now i just think they did not get enough sun or water. Anyway, i got 7 new ones planted in another spot in full sun and they have fully bloomed the past 2 years. However, just recently the problem has reared its ugly head again. My blloms are smaller now and not developing fully. From what i read it appears to be iron deficiency either from alkaline soil, too much phosphorous fertilizer,or over-watering. I read that iron deficiency impedes flowering among other things. i just sprayed with ironite so hopefully that will help.