Q.Poinsettia Transplanting
I live in the Ozarks of Missouri. I planted my Poinsettia outside and it has grown to about 3′ x 3′. It is a beautiful plant and I would really like to keep it alive. Can I transplant it into a large pot? How large is the root system? Can I cover it with a dark bag at night? I don’t have an area that is completely dark. If I can’t bring it in, can I mulch it and let it die back to come back in the spring?

Certified GKH Gardening Expert
They typically cannot tolerate temperatures under 50 F. So if it gets colder than this in your area, you'll need to bring the plant indoors. Dig it up and gently shake off excess soil. Then pot it up in a container large enough to accommodate its roots, which may be trimmed if necessary. Also, it may help to prune the plant back some to reduce shock setting in from transplanting. Here is more information: https://www.gardeningknowhow.com/houseplants/hpgen/prune-roots.htm
https://www.gardeningknowhow.com/ornamental/flowers/poinsettia/poinsettia-care-how-do-you-take-care-of-poinsettias.htm