I agree with Porkpal. The rose "knows" what it needs and responds to conditions as it should. If the leaves are still green, they are feeding the plant. Those turning yellow and spotting, will fall when they are supposed to. The yellowing is the plant sucking the chlorophyll out of them to recycle into new growth once the conditions support its growth. If they yellow and or spot, you will know the plant is recycling that chlorophyll in preparations to push new growth in spring. Until then, let it do what the conditions it is experiencing "tell" it to do. It ain't broke and doesn't need "fixing".
