I put this under a crabapple tree as a groundcover - the tag on the plant said it would only be a foot tall or some other nonsense. I really like the looks of it when it first comes up and it's short, but mine ends up about 4 feet tall and it's a thug! I'm thinking about just cutting it back with the lawnmower from time to time to keep it looking nicer. I think it looks ratty when it gets so tall and is not at all what I had in mind. I would try to pull it out except that it's already moving into the surrounding lawn, so I'm guessing that's not an option.
I have this plant and cutting it back with lawnmower or weed whip will not harm it , just comes back and looks good again in a couple weeks. If anything it may cause it to spread faster and you may not want that