Hello Marilee –
Some rose varieties can respond negatively to a liquid copper application. Any remaining leaves will likely drop when exposed to the copper fungicide. Follow these steps to control fungal disease in a rose plants.
1. Remove debris. Any remaining debris left over from previous years is a surefire way to propagate disease. Remove any old leaves, dead canes, and old mulch from the base of plants. Do not compost, but burn or destroy debris to prevent fungal spores from propagating in the future.
2. Increase air flow. By pruning your roses to increase the airflow between plants and between individual canes, you decrease excessive moisture and the environmental conditions that cause fungal diseases to thrive. At least five feet of space is recommended between plants.
3. Use a Sulphur based fungicide. Weekly applications of a sulphur-based fungicide will help to keep fungal disease at bay, while not harming your plant. Use a micronized sulphur for the best leaf coverage.
4. Provide optimum growing conditions. Roses under stress are more susceptible to disease. Providing proper soil that includes compost, peat moss, or aged animal manures in essential to healthy, happy roses. Regular fertilization during the growing season can work wonders. Roses prefer a slow release organic fertilizer, choose a product like Happy Frog Rose Food to keep your plants well fed all summer long.
Jumpstart Plant Tonic should help encourage healthy plants over the winter months, come February/March, or when you notice an increase in growth rate I would begin adding the aforementioned Rose Food to satisfy their heavy nutrient requirements.
Happy Gardening!
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