Let me start over ...
Welcome....
It's hard to help you when we can't see what you see. What I was seeing in the photo didn't match what I thought would make sense for a "hedge rose" that was six years old. That's why I suggested you look at the roots. If you did not have good drainage, the roots would show root rot, or if there was a fungal disease attacking the roots weakening the rose, it would be pretty obvious even to someone who was new to looking at the roots. Unhealthy material really does not look right.
We are all novices in one way or another, so don't worry about that part.
There are a lot of people here that just love helping people who are novices. Helping those who are new to parts of gardening is as much a part of gardening as putting plants into the ground and caring for them.
If you could share a photo of the plants in the ground where they are sited and a little more about where you are growing your roses, you may get some answers that may be far more helpful to you.
