With so many of us utilizing Knockout Roses in our landscape, it is unfortunate to report that a new disease is spreading through the Dallas area. Rose Rosette is a viral disease that distorts the growth tips and turns the leaves and shoots red. Thorn production is greatly exaggerated and they become soft and pliable. The disease moves downward through the Phloem into the root system and then back up through the xylem into new shoots. Eventually, death of the plant occurs.
Vectors of this disease include mites, root grafts, and infected grafting stock. It is also thought that pruning tools can be a source of disease transfer.
At this time, there is no cure for this disease. If you remove a plant infected with the disease, it is not recommended that you replace another rose into the spot as root material left in the hole will harbor new infections.
If you fear your roses may be infected, call your Arborist for a check up.