Knotweed Identification And How To Control Knotweed

For more information see Noxious weed lists and laws. Stems are stout, cane-like, and reddish-brown. The plants die back at the end of the growing season but their old reddish-brown canes often persist. The stem nodes are swollen and surrounded by thin papery sheaths. Leaves are either heart-shaped or spade-shaped or somewhere in between. The flowers are small, creamy white to greenish white, and grow in showy plume-like, branched clusters from leaf axils near the ends of the stems. The fruit is 3-sided, black and shiny.

General description

Control of knotweed is challenging and often requires a watershed approach to be effective along waterways. The King County Noxious Weed Control Program is engaged in several cooperative weed management projects in the county to tackle this difficult weed along certain waterways with assistance from local landowners and state and federal grants. For information on these projects, please see our Reports page or contact our office and ask to speak with the Knotweed Program Manager. Program offices are located at S. Jackson St. Skip to main content Animals, plants and habitat Noxious weeds. Weed identification photos Weed identification help. Invasive knotweed identification and control Fallopia x bohemica, Fallopia japonica, Fallopia sachalinensis, Persicaria wallichii, Buckwheat Family. General description In the Pacific Northwest, there are four similar species of invasive knotweed that are difficult to tell apart and share similar habitat, impacts and control methods.

Legal Status Public and private landowners are not generally required to control infestations of invasive knotweed that occur on their property in King County, Washington, except in selected areas on the Green River and its tributaries and on the Cedar River and its tributaries, as described on the King County Weed List. Identification Stems are stout, cane-like, and reddish-brown. Hybrid knotweed Fallopia x bohemica The most common invasive knotweed in western Washington, also called Bohemian knotweed.

What Is Japanese Knotweed, and Should You Try It?

Hybrid between giant and itadori Japanese knotweed and shares characters of both parent species. Itadori knotweed Fallopia japonica The most ornamental of the knotweeds and shorter than Bohemian or giant. Share your gardening knowledge with The Gardener's Forum - with 50, posts and thousands of participating members. No-dash-here, you've found The Real Garden Helper! Gardening on the Web since Plant Groups. Garden Plants. Gardener's Forum Gardening Questions and Answers. How to Grow and Care for Knotweed Plants. Search The Garden Helper:.

How to Identify and Remove Chinese Wisteria

How to Grow and Care for Knotweed Plants Persicaria bistorta Knotweed or Bistort plants are low maintenance, quick growing, semi-evergreen perennials with bright green, 4"-8" lance shaped leaves. They grow 2- 2½ ft. Once classified as Polygonum bistorta , Knotweed plants produce 3"-6", bottlebrush-like spikes of tiny, pink flowers on leafless stems that rise above the foliage from late spring into early fall. Knotweed is an excellent ground cover plant , especially when planted along the edge of a pond, a stream or in boggy areas.