Increasingly across Pennsylvania, it seems that the ubiquitous patches of multiflora rose are displaying symptoms of rose rosette disease.
This disease, first described in Canada, California, and Wyoming in the 1940s, has slowly worked its way across the range of introduced multiflora rose. Landowners and managers who have battled this invasive plant for years celebrate; rose growers lament.
Once infected, roses can show signs of the disease in as few as four weeks. There is no known treatment or cure for infected plants.
Rose rosette disease has many symptoms. It is most often recognized by a rapid elongation of new shoots, which often form clusters of small branches or "witches brooms." The leaves on these brooms are often small, distorted, and often red in coloration. The canes where brooms occur will often be soft and pliable, even the thorns have these characteristics, at least for a while.
Flowers forming on these canes may also display deformities. Infected plants often die in one or two years; however, some plants may live as long as four years. Some researchers report that infected canes are more susceptible to damage from low temperatures.
The Pennsylvania Forest Stewardship Program provides publications on a variety of topics related to woodland management.
For a list of free publications, call (800) 234-9473 (toll free), send an email to RNRext@psu.edu  , or write to Forest Stewardship Program, Natural Resources Extension, The Pennsylvania State University, 416 Forest Resources Building, University Park, PA 16802.
The Pennsylvania Bureau of Forestry and USDA Forest Service, in Partnership with Penn State's Department of Ecosystem Science and Management sponsor the Forest Stewardship Program in Pennsylvania.