It sounds like your roses may have . If possible, remove the infected leaves and treat the rest of the plant with a fungicide, which you can find in your local hardware store, garden center, or online. Powdery mildew forms when conditions are warm and humid, so if you happen to be watering your roses from overhead, try watering at the base of the plant instead to reduce moisture around the leaves.
It sounds like your roses may have . If possible, remove the infected leaves and treat the rest of the plant with a fungicide, which you can find in your local hardware store, garden center, or online. Powdery mildew forms when conditions are warm and humid, so if you happen to be watering your roses from overhead, try watering at the base of the plant instead to reduce moisture around the leaves.