Agreed, BB's should be left alone until you see new growth in the spring. Yours looks fantastic! Great job! Those pieces on the ground each want to grow a new bush for you... (enable, enable...) Mine were green all winter and one of them has buds that should open in the next few days. It's wild how early everything is happening in most places. I swear when I lived in OH (5b), it was the norm for BB's to just start showing leaves about this time, mid-April. Am I remembering correctly? Since BB's produce buds on old and new growth, and they do it rapidly all summer, there shouldn't be any fear about removing buds or delaying flowering, especially in this, the year without a winter. Even mid-summer when I'm deadheading, I'm very generous with the cuts when I see weaker, smaller buds in front of a much more robust node, and usually remove that inferior set. Once the branches get too long, they seem to lose their oomph. Still end up with a bush that's taller than me.

Personally I wouldn't prune it now. I generally prune mine back to 3' in the winter (Nov/Dec) and back to 1' (when possible) in the early spring. I have never pruned them this late in the season, so I can't offer much useful advice. As for transplanting, I wouldn't do that either right now, especially if it's well established. You'll get more useful information; if not, try asking over in the butterfly forum.

I think you can prune them as short as you would in early Spring...they should just grow right back and then bloom. They are very hardy. Joann

Call me a nut, but I have LOTS of these growing which I started from seed. The oldest are about 6 years old and two were planted 1 foot apart. They've grown very well every year reaching at least 7 feet last year. If you do plant 4 feet apart, I wouldn't plant something in between for the plain and simple reason that it will be hard to access when your BBs are mature.