You'd get better results if you inserted teh cuttings into a pot of compost and put a bag over it to keep in moisture until they're rooted. If you have a scratch around the bases of your existing plants, you may well find some of the stems have rooted where they touch the compost. You can just sever those and plant them where you like, but keep watered until they're established.

If its in a spring planter, i.e., a container, if its been there a while, turn it out, pull the rootball into two sections, keeping some root with each, and replant as two different sections. I'd keep the one you want for the garden in a pot until it recovers a bit and starts growing again.