Mine have not done well at all this year. I have 3, and in differant locations. My DH saw a bloom or two on one. I haven't seen any. I presume it is because of the hard spring freeze...but you would think all the rains we have had would have brought them on. :-(
Maybe the voles have eaten their roots!
The year that they did best they did rebloom during the summer. I seldom cut them back, but did after the freeze. Hopefully they will surprise me with fall blooms.
I see beautiful ones in other people's yards.

I always cut mine back to about a foot in March and they bloom around late May but are done but around mid June it seems. I did cut them back again after bloom this year to see what would happen but didn't trim them back quite as short as I did in March. Maybe they'll bloom again.