Kudos to you for keeping such healthy looking plants in pots, no less! I overwinter mine in an unheated sunroom where they don't go completely dormant or I put them in a garage type space that stays in the 40s. I think the latter is better and even colder would work so long as they don't totally freeze. Dark is fine as well. They will need occasional watering. I give mine a good drink before I put them away and only give them more about once a month. Those in the glass vestibule are treated the same, but were more difficult to care for as when it warmed up in the spring they had an aphid outbreak for which I sprayed. Those were smaller pots however, so I was able to bring them outside earlier and had bloom from them at least a full month in advance of my others, so that was inspiring! If I had more space, I'd definitely go for the coldest (not freezing), darkest spot I could, so long as you can get there occasionally to water them. Moses and others do similar with some even putting blankets on them in unheated, uninsulated garages.

I would take them to your in-laws garage. An insulated but NOT heated garage is the best way I know of to winter potted roses. The only things you need to do are: put them up on some wood blocks so they're not sitting on the concrete and water them about once a month all winter. It doesn't have to be a lot but they will need some water all winter. When I had one in my shed I used to put a snow shovelful of snow on them every time it snowed. If there are windows you might also position them where they won't get a lot of light so they'll stay dormant as long as possible and, if you can, protect them from any cold blasts of air when you open the garage doors. Those two aren't mandatory but can be helpful. The most vital part is the watering. Yes, roses do die from the cold. But temps need to go into single digits and stay there for some time for that to happen. More roses die from dehydration than cold. If you winter them outside that's not as much of a problem because they'll get rained and snowed on. But roses wintered inside don't have that so you have to do the watering.

Seil- is it possible to winter them outside? I figured not since the soil would most likely freeze in a container.

I do winter some outside but I'm in a warmer zone than you and I take extreme measures to protect them.

It's a lot of work to put them in each fall and just as much to take them out come spring. As I've gotten older it's become more than what I can handle so we're cutting back on all the pots. At the height of my addiction we had over 60 in pots. I'm down to about 15 now and eventually they will all go.

Shelby,

Nothing more to add to the excellent advice from Vapor & Seil, except to watch for temps in storage that go below 25°F. for more than a short while, stretches over 4 hrs. length. Below 20°F. ever is dangerous. Most hybrid tea types' canes turn black at 17°F. or lower.

Moses