I purchased this very small plant (like a plug) 3 years ago from Spring Hill Nurseries for $19.99. It has done nothing!! When I thought I had pulled up all coneflowers in this section, I missed this one. As it grew, I cut it back and when I bought the artesmia moss plant, I was going to pull it out. For one reason or another, I kept putting it off. This past Monday, that was on my "to-do" list, but I got tired from weeding and didn't. In just a couple of days, this plant has come alive. I'm happy I did not pull it up now.
This is what it is going to grow into: