Sounds like the rosebush has become Root Bound. When left in containers too long, their roots start to grow in the shape of the container. When the roots become wrapped around enough, they strangle one another. The rosebush can no longer take up all that it needs to survive and dies. I have seen this many times and once they get that root bound, there is no way to save them. I have tried taking them out of the container and trimming away some of the roots and replanting. Just did not work. Sorry to say....
Answered on June 8, 2021
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