What Mike said. I'm thinking it's not draining properly. And it's entirely possible that the one side is wetter than the other so one rose is OK and the other dies off. Dig your hole and then do a drainage test. fill the hole to the top with water and walk away for an hour. If there is still a lot of water in the hole when you come back there is not good drainage. Either dig deeper or create a small french drain for the excess water.
Tantefrancine, that is called rose replant syndrome and it is really not a problem in the USA. They do have some problems with this in Europe but not here. If it were I'd have no roses, lol! I have a small yard and have had over 300 roses at one point. I ALWAYS reuse my holes! And I NEVER replace all the soil.
Lola, I was think a pretty clematis on the other side. A deep purple would be beautiful with that yellow rose!
