Last year this boneset wildflower -- the big white-blooming behemoth at the top -- did very, very well. Too well, since it cast a large afternoon shadow that denied sun to a big chunk of my veggie garden. So I vowed to never let it grow that big again. I think I'll let it get to about 8 inches, prune it continuously, and see if it blooms.
Hard to believe that this huge shrub would grow again from this single little rootlet (not the right noun...stump? trunk?) September 2010 (top), April 2011 (bottom).