Your obedient plant (Physostegia virginiana)---what color is it? I used to have two that grew in heavy, poor soil in a very hot area---next to a building on the west side. One was a pretty pinky color and she was a floosy! She liked to spread herself around. Since she was so pretty, I decided to put up with her and each spring I'd take a shovel and trim the whole plant back to the size I wanted. She didn't mind at all. Her sister is white ('Summer Snow') and she is a perfect lady. Each year she gets a bit bigger and occasionally I find seedlings (I like that!). When we moved, only the well behaved (obedient!) white sister made the move with me. FYI I live in Portland OR.