I bought a vacation house in Ukiah, and I bought a number of rose bushes all from reputable nurseries and none of them from places like home depot or other big box stores. Three out of the seven have come down with Rosette Virus. It is important from everyone who grows roses to familiarize yourself with Rosette and check your roses often because the virus is fatal unlike Mosaic virus and can spread from one rose to all your roses resulting in the death of your entire rose collection. The most dangerous rose to grow is the Knockout Rose. This rose is genetically modified. I believe genes were added from Rosa Multiflora (a noxious, evasive weed) to create roses that can be planted anywhere in any soil and ignored. If you go to You Tube there are large numbers of videos uploaded from conferences on the Rosette Virus. It is spread by contact or by a mite called Eriophyid mite (Phyllocoptes fructiphilus). Also you need to bleach your pruning sheers in between changing from one rose bush to another. The mites are invisible and there is sometimes there is no way to tell if the bush has Rosette. I read some of them seem to "recovery" and can live for as long as five years, but at this time will still be spreading the virus.