Answer: Black spot is a common disease of roses grown in the Pacific Northwest. You've done the right thing in removing affected leaves before the disease has a chance to spread to healthy plant parts. Insecticidal soap will kill soft-bodied insects, but won't protect your roses from disease. For that you need a fungicide. It will also help to prune your plants, and adjacent plants, so there's plenty of room for good air circulation. Try not to splash water on the leaves when watering, and water in the morning so the leaves have a chance to dry out during the day. There are some cultivars that are more resistant than others to black spot, so if you plan to add rose bushes to your landscape, be sure to find those that have the best resistance to disease. For more information on roses, contact the American Rose Society, P. O. Box 30,000, Shreveport, LA 71130-0030.
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