I put a few *tiny* sprigs here in March. Time to pull it up from this spot, starting to grow over the other plants. Will move to a new spot where it can have more room. Even where not hardy, it can be used to decorate the landscape, as well as making a fine potted plant or accent.
Ground covers that aren't hardy are easier to deal with anyway, IMVHO. No concern about it running too wild or boredom.