Q: We have Knock Out roses in our subdivision landscape and are planning to add more. We have heard that a virus is beginning to attack roses. Should we be concerned about this to the extent that we not add any more?
A: If the roses look healthy there is no need to substitute other plants. Rose rosette disease is transmitted by mites, not by contaminated soil or water. If you don’t have infected plants in the vicinity, any new roses you add will grow fine. However, examine any new roses for excess thorniness and a distinct reddish cast to the stems. These two symptoms are common on rosette infected plants.