Answer: If the shrub is otherwise healthy (new growth, flowers, etc.) then the problem is typically a symptom of a nutrient deficiency. While you may feed your roses on a regular schedule, the soil's pH could be binding up the nutrients and making them unavailable to the plant. Soils in western Washington are usually acidic. Roses grow best in a neutral to slightly acidic soil. I'd have the soil tested. You may need to lime your rose bed this fall to sweeten or mellow the soil. Just how much lime you may need to apply will depend upon your soil's pH.
Best wishes with your roses!
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