Answer: Yes, you can prune for enhanced bloom, although pinching isn't usually done with asters. In my experience it works well to cut the plant back hard or shear it off by about half in late spring. This promotes denser branching and consequently produces more blooms. It also causes the plants to bloom a bit later in the season and in some cases keeps the plants a bit shorter than they would be otherwise. It's especially helpful with the larger asters but works well on the small ones, too.
Q&A Library Searching Tips