Horticultural fleece over both the rose and the pot will help - bubble wrap can get very wet inside and if it then feeezes the pot can break, most care is for the pot not the plant as roses in pots do fine whatever the weather throws at them. If we are going to get the temperatures we did 2 winters ago, then two layers of fleece with newpaper between them should cover most eventualities - it has done so here so far, East Midlands. I agree with Cristopher2, I keep them on the dry side - just allowing whatever falls from the sky to keep them going. We never water in winter, this applies to just about all our many pots.