According to author and horticultural professor Jeff Gillman, who has conducted extensive research on blackspot remedies, a spray composed of one part milk and two parts water is the best answer to the disease. He says this simple solution, if applied weekly, will control blackspot as well as any synthetic fungicide, including Chlorotalonil.
ROSE SPRAY-helps prevent diseases such as rust, blackspot, and powdery mildew. Mix together: •1-tablespoon baking soda •1-teaspoon mild dishwashing detergent •1-tablespoon vegetable oil •1 dissolved aspirin Add: •1-gallon water Mix together and pour into a spray bottles. Spray roses every 1-2 weeks.
In general, remove dead, damaged or diseased stems as soon as you see them. Find out the best time to trim hydrangeas, fruit trees, clipped hedges, roses, deciduous shade trees, evergreens, pines, shrubs, annual and perennial flowers, and berry plants. Also, check out our tips on how to prune different plants!