My roses develop Rust every year like clock work, and I haven’t been able to eliminate it. They face west and get about nine hours of sun. The affected varieties are Mustard & Ketchup, Radiant Perfume, and Sterling Silver. Any help?
Try increasing the water. Water stress can force, literally, even resistant types to both mildew and rust. It won’t cure every case, in every location, but it may help with some of it. I had read of the water stress induced mildew in rose books and tested the idea. It worked. I accidentally discovered the water stress induced rust by drying out a potted R. Arkansana in spring, forcing the whole thing to rust from top to bottom. I removed the foliage and watered it copiously. It broke out in gorgeous, healthy new foliage. I waited several weeks and deliberately dried it out again and it again rusted. So, to test whether your roses are experiencing water stress induced rust, increase the water and see if it helps. It might, or it might not, but at least you’ll know if that is a factor. Nine hours of western sun can easily induce water stress, particularly if there is hardscape of any kind close to the bushes. I hope it helps. Good luck.