Noxious Weeds That Harm Washington State

sulfur cinquefoilPotentilla rectaIdentification: Sulfur cinquefoil is a perennialplant up to 3 feet tall. Palm-shaped leaves have5-7 leaflets that are covered in stiff hairs onboth the upper and lower surfaces and are finelytoothed. The flowers are pale yellow with 5 heartshapedpetals.Impact: Sulfur cinquefoil can form densestands that displace native and beneficialplants and grasses. Because this species is notpalatable to livestock and wildlife, infestationscan significantly reduce the forage value ofrangelands and pastures.Control: For small, scattered patches, thesimplest control is to hand-pull or dig up anddispose of plants and roots. Selective herbicidesprovide fair control of large, well-establishedinfestations, but treatments are more effectivewhen combined with other control techniques,such as planting competitive grasses.W-20