Can't seem to find the answer in my Sunset bible, or on the net, so
asking this good group.

Thses are established, 2 yr old, plants and blooming nicely. Should one
cut them back at some point? Do they take well to dead-heading? Plants
are quite well filled in and close together and I'd like to keep them
so. Don't want them leggy.

Your opinions appreciated. TIA , Nonnie