A friend of mine moved provinces and it's incredibly hard to get simple plants, so I wanted to send some clippings of Moneywort to him. My moneywort is probably over 6 inches long because I've never trimmed them before, do, I just cut anywhere on the stem, for e.g the very middle of the stem, or...

I want to order some plants from the swap and shop but I'm afraid they won't make it to me alive. I live in michigan and its been downright cold in the teens and some cases below 0. Should I wait till spring or is it ok to get them shipped? Or can people put a heat pack in or is there a trick...