I read to estimate winter in a large pot is at least one zone lower than in the ground. You would want to choose a very hardy rose if you are growing it in a container.
You definitely want good drainage soil mix and containers. Two of my outdoor containers look like melting popsicles today. They were frozen solid. I can't drain the water because they are still frozen solid to the ground. Other planters were covered in snow all winter. The snow is up to the rim of the pots.
I amend planting holes with peat moss and compost or manure. I also use Bayer systemic rose disease control products. I top dress the plants monthly. Some people like RoseTone. I haven't found it in the local stores.
