The only reason I will let a few of the spreading Physostegia virginiana, or obedient plants, stay in my yard is because they attract butterflies. If you have this plant, you know it spread by runners and will pop up several feet away from an existing plant. Otherwise, it is pretty easy to pull to control, but you will need to do this, unless all you want is a garden full of obedient plant! (The name comes from the habit of the flower to stay in position when you bend or twist it).
Enjoy the butterflies as they flutter by!
*Lagniappe: Cajun for "something extra."