The last few years seem to have been favorable for the establishment and spread of multiflora rose in pastures, on Conservation Reserve Program acres, in timber and in other areas that are not annually disturbed.
"Late spring is an excellent time for controlling MFR since herbicide applications at this time generally provide more consistent control than applications made later in the growing season after flowering," says Bob Hartzler, Iowa State University Extension weed management specialist.
Numerous herbicides will provide effective control of MFR when applied at the right time and manner, says Hartzler. He put together the following table which provides information on some of these herbicides. Many of the active ingredients are off-patent and sold under different trade names.
"Precautions should be taken to minimize off-target movement that may result in injury to desirable plants," says Hartzler. "Check labels for any restrictions that may pertain to use near water resources and for grazing of treated areas."
"Weed control specialist Mark Loux and others at The Ohio State University have prepared an excellent, in-depth bulletin titled Multiflora Rose Control that provides detailed information on multiflora rose and the effectiveness of chemical and other management tactics," says Hartzler. He suggests you click on this link and read that publication for more information.
Multiflora rose (Rosa multiflora Thunb.) is a thorned bramble perennial plant that now infests more than 45 million acres throughout the eastern half of the United States. This plant's name is derived from the many clusters of white flowers borne during May and June. Older bushes can attain a height and a diameter of 15 feet or more, with a basal crown diameter of 8 inches.
Takes time, a plan and staying with the plan to eradicate MF rose
Dense multiflora stands severely reduce pasture grazing for cattle, as well as the accessibility and usefulness of other noncultivated acres. Severe multiflora rose infestations may lower land values both for agriculture and for other uses, such as recreation and forestry.
Multiflora rose can't be eradicated by a one-time destructive effort, says Hartzler. Wherever multiflora rose has become naturalized, the soil near older plants soon contains a large seedbank. One plant can produce up to one-half million seeds per year, which can remain viable in the soil for many years. Birds and other animals disperse seeds across a wide area, but the relatively few seeds brought by them into a property where multiflora rose already has become established are of minor consequence. Therefore, if a pasture cleared of older plants is subsequently left untreated, multiflora rose will re-establish primarily in areas where it existed earlier.
Multiflora rose can also multiply by layering, the process whereby tips of canes that touch the ground develop roots. New plants can also arise from the shallow roots of older live plants. Several scattered multiflora roses, if left undisturbed, can form a dense thicket within a few years. "Many people have the misconception that they cannot successfully suppress this plant, but if you keep after it you can get rid of it," says Hartzler.