Austin site has a list of roses for containers.

Get large containers. You can move them easily with a two wheeled dolly. I use 7-10 gallon containers for my potted roses.

Karl:

Is that nursery size gallon or actual size gallon?

FJ

Most of my roses are in containers, and all are Austins; I have 30+ Austins. I use big containers, either 1/2 or 3/4 barrels or 25-27" pots for the individuals, and huge planter boxes for multiples. I used vermiculite and/or perlite with soil in the bottoms of the big pots, and then a high-quality potting soil over that. I feed regularly with a good organic feed (Dr Earth) and use epson salts a few times a year. Since they are English roses, I prune minimally or not at all. Having great success, lots of blooms, minimal disease (which is also my area) and other than squishing aphids and dead-heading, care is easy - water OFTEN, like daily if it's hot. If you can, order your bareroots directly from Austin in TX, that's where almost all of mine are from and I love their customer service and the health and size of the plants.

Nursery size. The difference in the amount of soil in pots that large, whether nursery size or actual gallon, is not that important.

Just a thought I'll share on something that i have learned through experience on growing roses in containers.
Don't plant a small plant in a big container from the start.
Re-pot the rose as it grows into increasingly larger containers as needed.
If you don't, the bottom of the container will remain too wet, even if your potting mix drains well, and your roses will not like it.

Randy

I agree with Randy 100%. If you plant a small rose in too large of a pot, the soil in it can sour and the plant will not thrive. They seem to do better if you keep potting about one size up until you reach the size you want to keep it in.

I never use the moisture control potting soils either. I've lost a lot of roses with the stuff. Trish from Ashdown has had the same experience. I now use a good organic based potting soil, and sometimes mix a little compost and Mills Magic Mix in with it. They'll aslo need some liquid fertilizer on a regular basis to stay healthy. My roses remind me with pale leaves when I get lax about it.

Sandy

I grew roses in pots for years in zone 4/5 (I still do down here). I overwintered them back in WI in my unheated attached garage.

Late in the fall I would cut the roses back to about a foot or so and remove all the foliage. Then I'd water them real well. Once the pots are drained I'd slip each pot into a 55 gallon black plastic garbage bag. You can find these at Farm and Fleet type stores. Fold the open end over - do not tie them shut so air can get inside. Prop the bagged roses up off the cold cement floor on wooden boards. The plastic bags will help keep the potting mix moist all winter. My hubby and I used to come down here for 3 months during the winter and nobody was watering them in my absence! In the spring take the roses outside and out of the bags. You should see pale yellow shoots forming. This is a good sign cuz you will know the roses have survived the winter! Remove these spindly shoots because they are fragile and break easily. Water the pots well and place them in full sun. (You can bring them back into the garage overnight if a real cold night is forecast.) Once you see new normal colored growth you can begin to fertilize and spray if needed/wanted.