I have 30 or so roses in pots at the moment, and they seem to be doing very well. Some were body bag roses that I wanted to quarantine, and others were bare root purchases from late season sales at good online nurseries. A few were purchased as potted plants already blooming. Of all, I think the fully grown ones need to go in the ground SOON. They are looking stressed from heat, and maybe are getting a bit root bound. In the past, I've had trouble with the pots getting too hot, but this year, I placed them in among plants in flower beds so the sun wasn't hitting the sides of the pot directly. We are getting rain and humidity that normally we don't see this time of year, so it does feel like Florida here! My thinking is usually to get plants into the ground asap because they need to be established to make it through winter. You don't have those worries there. In a pot, you do have the option to move a plant into a more protected site if it needs it, and you have better control over water and nutrients. Those points might sway me if I were in your shoes.
