Originally Posted by andyslawncare
I blame on old age and lack of juvenile pruning + shade. I've noticed very healthy azaleas and camellias in the same beds; the roses are healthy too, just old. The roses are still blooming today.
You have provided enough information for me to say you should know the problem. You have stated they are sparse and have been since doing a rejuv pruning last year, and azaleas and camellias are in the same bed but thriving. I do it would be stretch to imagine that those roses are not the right plant for that place.
Although I agree with ed that roses are generally heavy feeders, in your case I do not think fertilizer is the answer until they are moved to a location which allows more favorable growth conditions. More fertilizer could essentially cause more stress.