If you want to try buring remember
you have to get below the frost line.
Here it is @ 24 inches. If you do not the
roots will freeze & your rose will die.

Some people here on the hills can get away with mulching, mounding, etc.
Hills can be up to Z3 or Z4 even on the south sides. I'm in a valley.
:-( I put some daffy bulbs in the prospective rose bed last fall and
covered it really well, figuring that if they survived roses might, but
alas, I finally dug in last week to find some really icky squishy bulbs.

One question I do have is: honestly how cold can a rose take, say,
overnight? Can they do down to the 20s or lower if it warms up in the
daytime? I think I took mine in too soon last fall, right after the
second or third frost, and they had a hard time going dormant.

Thanks, Kim