The last few summers have brought attention to cases of Rose Rosette Disease. Since so many landscapes have Knockout Roses, seeing RRD is becoming more common (but it is not rampant) and we find ourselves fielding questions about “What is wrong with my roses?”
RRD is a virus spread by tiny mites and the most obvious symptom is “witch’s broom” (very red and thorny stems with bright red foliage). There is no cure for RRD and the plant will likely die within 2-3 years. However, a preventative miticide program for your roses can keep the disease from infecting the plant to begin with.
When a rose is found to have RRD, if it’s only on one cane, follow the cane all the way to the ground and cut it off. You’ll know within the next year if the RRD was contained to that one area. If not, the entire rose needs to be removed, roots and all, from the ground and disposed of by burning or placing in a landfill.
One way to keep RRD from being transferred from plant to plant, is to take precautions when pruning. Clean your shears with a 10% bleach/90% water solution between plants and/or cuts.
Cleaning your shears when pruning is a good practice anyway, but especially with roses.