This disease, thought to be caused by a mite-transmitted virus, is endemic to the Midwest where Rosa multiflora hedges are frequently planted and become infected. The disease occurs sporadically in the United States on cultivated roses. Cause Rose rosette virus is reported to be the cause of rose rosette or witches' broom, although the virus etiology has not been proven. Symptoms Figure 5. An early indication of infection by rose rosette virus is rapid stem elongation.
Leaves are deformed, wrinkled, and pigmented a bright red.
Blossoms often are aborted, deformed, or converted to leaf-like tissue. Unlike the mosaic diseases, rose rosette is fatal to infected plants. An infected rose usually dies within two years as symptoms spread throughout the plant. The rose gardener should immediately remove plants suspected of having rose rosette. This, along with spraying with a miticide, will reduce the chance of spreading the disease to healthy roses.