We have about 15 Annabelle Hydrangeas along our fence. They were planted about 8 years ago and have grown quite well.

My question is two fold:

(1) When to cut back?

We usually do so in the fall. I think we've been cutting back too far, as I've been reading that you should leave about 24 inches. I've also read that the better time to cut back is in the spring, after the last frost. We are in the Chicago area.

(2) We also want to strengthen the plant stems. They are extremely floppy and seem weak to me. Also, the blooms have become quite large the past couple of years. Is there anything we can do, as far as pruning goes, to get these stronger - and perhaps encourage more, smaller blooms?