I live in California and we get some frost in the winter, but almost never does it snow. I do all my rooting in winter. My best luck has been from putting the cuttings in big plastic cups that have drainage holes, about 3-4 cuttings per cup. Then I either put the cup into the ground or into a big flower pot if I am doing several "cups". I surround the cups with potting soil. The benefit of this is you don't need to disturb the roots in spring when you remove the cups and if you have enough roots, you can slip the entire root ball out and into its own pot. Newly rooted cuttings are very fragile if you don't do this, I have found. I have put six large cups of rootings into one flowerpot and had six plants in spring. I don't do it often, as my space is gone, but we have damp, cool winters, just perfect for rooting roses.

Love them plastic cups.

If you use clear plastic ones, you can see how the roots are developing, without disturbing them.

Jeri

I second kathy on the info. that own-roots are very fragile. When I transferred them from pots into the ground I often broke half the roots off. Lesson well learned.

Don't keep your roses indoors: they hate it there, it's the worst place for them, too warm, dry, and dark. If they're bare root or in pots you can probably pot them or leave them in the pots to grow, keeping the pots on the ground and covering them with a sheet or blanket when you get freezing weather. Or, if they have any root system at all, you can simply plant them right now in well dug holes, and not worry about them. Roses don't mind temperatures in the twenties or even the teens if their roots are protected. I root my cuttings over the winter in open beds, and also keep numerous plants in pots, and they all live through frosts in the upper twenties, and sometimes lower temperatures. Last winter we had three weeks when the daily lows were in the middle-low teens and never rose above freezing, but there was also a foot of snow on the ground, while we insulated the pots with hay and old sheets. We lost plants in the cold greenhouse, but everything that was on or in the ground lived and suffered no damage.
Melissa

Thanks, Melissa, I always learn lots of good tips from you - much appreciated. My zone 5a winter dips to -20 degrees F., even lower with wind chill in Chicagoland. The rosarian Karl Bapst, zone 5a, told me to put baby roses to sleep in a DARK, UNHEATED garage and water them occasionally. You are right about not keeping roses indoor: too warm and dry.