How to amend soil for roses

I live in Amherst, NY.

I am new to taking care of roses .

I have 2 existing climbing rose bushes and I have started a whole new bed to plant 3 new hybrid tea rises . I had my soil tested and the ph is 7.3 .

My Savid Austin climber blooms beautiful in June but then throughout the season the leaves start to die back and looks terrible.

The other climber is fine .

I want to sprepare my new bed so my roses have an optimum growing condition. What should I do to the soil?