The Washington State Noxious Weed Control Board is considering several significant changes for next year’s state noxious weed list. These include adding small-flowered jewelweed (Impatiens parviflora) and European coltsfoot (Tussilago farfara) as Class A and B noxious weeds, respectively—additions originally proposed by the King County Noxious Weed Control Program.
Small-flowered jewelweed is a widespread invasive annual in Europe, native to parts of Asia, that was recently discovered in Washington. It often grows in shady areas like forests, riverbanks, and also disturbed or cultivated sites. The plant is usually 1 to 3 feet tall and has tiny, pale yellow flowers, each with a short, straight spur. Like other Impatiens, this plant reproduces through seeds that rocket out of their seed pods when touched (hence another of the plant’s common names, “small-flowered touch-me-not”). There are currently only two known small-flowered jewelweed sites in Washington State, both in King County. One location is near the Woodland Park Zoo in Seattle and the other is east of Redmond in northeast King County.
Read more at Noxious Weeds Blog