|I had several new cone flowers damaged by a recent storm. The stem was broken on each down to about 1|
|I would cut off the damaged plant parts (to keep insect and disease problems at bay). Coneflowers are rampant growers and should be able to recover. Look for new leaves and stems. I expect they'll even flower later this summer. If not, at least they will be able to expand their root growth and be stronger next year - at which time you should have lots of flowers.
Best wishes with your garden!