Struggling with Julia Child — would appreciate advice

I want to be honest: I'm not getting great results with Julia Child and I'm not entirely sure why. powdery mildew in humid summers has been a recurring problem despite my attempts to address it. I've been focusing on applying rose-specific granular fertiliser in early spring based on everything I've read.

exceptional fragrance on warm afternoons is there in glimpses, which tells me the plant has potential in my conditions. I have it in a dedicated rose bed with good air circulation which might not be ideal. first flush of blooms in late spring showed some improvement. Two stars for now — not the plant's fault, but not a success yet. I'll update if things improve.