Some good advice from Thanrose.* I would suggest you pot it up now before the roots get more established and plan on bringing it indoors befofe you turn on the heat for the winter.* You could also take cuttings and start new plants each year.* Here's how to move plants indoors and outdoors each year.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.