Do you have an unheated garage or shed? I have my potted tree rose in my shed. It's too warm in the basement even though it's unheated and that's why they've sprouted out. And you're right they won't like it down there all winter. You'll get nearly white spindly growth that is not good for the rose. If you put them in a garage or shed make sure they are well watered going in and check them for moistue occasionally. You also want to get the pots up off the floor some how on wood or blocks. Hope this helps.

I winter mine against the house. I build a wall with burlap and then pack them with leaves. 6 winters now and they seem to do very well that way. I do have one tree rose that goes into the shed because of the graft being up so high up. I wrap it with newspaper and burlap and put it into the shed. If you do put them in the shed or garage you need to do two things. 1. Put them up on wood blocks off the cement floor. 2. Water them a little once a month. Drying out can be deadly for them. And if you leave them outside pile snow on them when you shovel. It's good insulation and it also keeps them moist. We snow blow toward the roses so they get a good blanket all winter.

Follow Michael's and Susan's advice and it should be fine. I keep my rose tree in my shed for the winter and in the spring when things start to warm up I can tell when it looks like it wants to start budding out. That's when I wheel it back outside into the light. If there is going to be a deep freeze I wheel it back in. That's when the wheeled pot trolley is the most beneficial. It makes it much easier to move that big, heavy, tall awkward pot in and out. I've been doing this for 6 years now and it's still doing great!

I've tried three times but even with sheltered winter protection they only last a couple of years before they die off. I've given up on them. The problem is keeping the graft at the top alive not just the root ball. The freeze and thaw way up in the air is the culprit. You can't protect that well enough to keep it at a stable temperature.