Description:
Sulfur cinquefoil is a perennial species with a woody rootstock. It produces several erect stems which can reach one to three feet in height. The stout, leafy, hairy stems are unbranched up to the inflorescence. The leaves, which are also rough-hairy, have five-to-seven-toothed, palmately arranged leaflets that are two to four inches long by 1/2-1 inch wide. The flat-topped inflorescences are three to six inches across, and each flower has five light yellow petals surrounding a dark yellow center. The fruits are achenes, which are dark brown, with lighter, prominent, branched ridges, and narrow, winged margins (Callihan et al. 1991; Werner and Soule 1976).

• Mechanical: In productive areas, cultivation with annual crops will control sulfur cinquefoil. Hand pulling or chopping is also effective if care is taken to remove the root crown. Because the massive, woody root system stores extensive food reserves, mowing is not an effective control measure; the roots send up new shoots after mowing (Rice et al. 1991).
• Biological: Forty-seven species of insects are associated with sulfur cinquefoil in the northeastern United States. These insects need to be investigated for biocontrol potential. However, because of the close genetic relationship between cinquefoils and strawberries, there is concern with bioagents attacking non-target plants and crops (Batra 1979).l
• Herbicide: Tordon (picloram) and 2,4-D ester both provide effective control of cinquefoil without harming grasses (if applied at recommended rates). Ally (metsulfuron) will also control cinquefoil, but may cause grass injury. Sulfur cinquefoil will re-establish within three to four years of herbicide treatment, so repeated applications are needed for long-term herbicide control (Rice et al. 1991). Refer to the State Noxious Weed Control Board site

For More Information:
Detailed information about Sulfur Cinquefoil is available at the Washington State Noxious Weed Control Board Web Site.