Knowledgebase
Possible RRD in Chisago County #872579
Asked June 11, 2024, 10:33 AM EDT
Chisago County Minnesota
Expert Response
Unusual growth on your rose could be Rose Rosette Disease (RRD). RRD has been documented in Minnesota and is present in over 30 US states. Symptoms of RRD include excessive thorniness, clustering of small branches (witches' brooms), unusual reddening of stems and foliage, and abnormal, late-season, lateral shoot growth. These symptoms can be variable and may not always be present, so it's important to monitor the plant closely for any signs of these symptoms.
I cannot tell from the attached photo if your rose has RRD. It needs to be diagnosed by a professional to be sure. I recommend contacting the Plant Disease Clinic (https://pdc.umn.edu/) at UMN for testing.
Once a plant is infected, there's no cure. Pruning to remove symptomatic canes is often ineffective, as the mites may remain on the plant or in recently infected canes. The virus can also survive in the root system. If RRD is identified, it's recommended to dig up and dispose of the plant and avoid planting another rose in the same area for a couple of years.