Rose Rosette Disease is thought to be a virus introduced by the wild specie rose Rosa multiflora. It’s spread by a wingless microscopic-sized mite that is blown about by the wind.
The symptoms may vary with the species and cultivars. Abnormally elongated shoots developing witches’ brooms (small clusters of distorted leaves); excessive growth of soft thorns colored red or green; distorted growth – thicker canes contorted onto spirals: aborted buds, often misshapen or distorted flowers, are some of the indications.
The sad news is there is no known cure and once infected, the plant dies within a year or two. To keep the disease from spreading to other roses in the garden, it’s recommended any infected rose be removed ASAP, being sure to dig up and remove all the rootstock below ground. The infected rose and all refuse should be burned or carefully bagged up and placed in the garbage. Do not put any of the refuse from an infected rose into the compost pile.
After removing the plant, clean any tools used, such as shovels, loppers and pruners with a disinfectant, such as a mix of 9 parts water to one part bleach. Oil the blades of the tools after cleaning.
Removing any wild roses (Rosa multiflora) from the vicinity of garden roses will help to prevent infection. Spraying roses with a miticide, such as AzaMax, an OMRI listed organic product, every ten days during the months of May and June may provide some protection.