You can also try packing the whole pot in a black plastic foil, wrapping it around the trunk with a tie-wrap, making it air- and watertight. Make sure the tree has enough water (but not too much to let root-rot kick in) before you do this. Because the black foil will attract warmth, this will encourage new root growth if the tree still has any life in it. Then place the tree in a dark(er) and cool(er) place where there is no wind for the first week or three to let the tree recover. During this stage you can just hope for the best as there is not much chance thee tree will revive again. Once you notice the tree starting to show some life again (I mean creating new buts), remove the foil and leave the tree in de darker place for a few more days (till the buts starting to burst) before slowly (day by day) starting to move the tree to its original place. You do not want to fertilize the tree at all during the first month(s) as this would likely cause the new roots to burn. You may also want to wash any remaining fertilizer out, if you think there is still much left in the soil. Good luck, as you will need it!

I order bareroots for last week of March, with the idea of getting them in the ground the first week of April. Remember, bareroots aren't planted in spring, but the end of winter. If they don't get snowed on at least once, they are planted too late. I wouldn't plan anything different for this year, but the beginning of May is getting into territory where if they honestly can't be planted, they go into pots. They have to get into dirt and start growing or they won't survive the challenges of the next year.

Yes, trim off any dead wood. You may lose those early leaves if you get another freeze but the roses should still be OK and leaf out again. If you know it's going to freeze can you move the pot into a garage or shed to protect it some?

Rebecca, it is possible for the rose to have rrd but there would not be any living eriophyid mites on there to spread the disease. The e-mite is the only known vector/spreader of the disease rose rosette. There are not many reported cases up your way but they are there. Heck you could visit a rose garden and bring a mite home on your clothing. They can't fly and so depend on the wind, insects and other means on transportation to get to your roses. Hope that this helps.