& Zucc.) Evaluation of Imazapyr, Glyphosate, and Triclopyr for Japanese Knotweed (Polygonum cuspidatum Sieb. One popular Japanese Knotweed herbicide treatment method is the leaf application of herbicides, also known as foliage spraying. It grows in dense patches to heights of 10 feet, on sites ranging from strip mine spoil to shaded streambanks. Herbicide treatment for Japanese knotweed. The best time to spray the leaves of Japanese Knotweed with herbicide is late summer or early autumn. This herbaceous plant (sometime referred to … The Process. 14oz/acre for Japanese knotweed. It is native to Asia, and was originally introduced to the U.S. as an ornamental in the late 1800's. They are all glyphosate-based herbicides and will kill the troublesome weed. By being a cost-effective way of controlling knotweed, the gallon herbicides can effectively cover an area of more than 25,000 square feet. Report on knotweeds from the book "Weed Control in Natural Areas in the Western United States" Cowlitz County NWCB Fact Sheet on Japanese knotweed. Control Introduction Japanese knotweed is a federally listed invasive perennial native to Asia (National Agricultural Library 2004). See our Written Findings for more information about Japanese knotweed (Polygonum cuspidatum). This DIY Japanese knotweed killer recipe works best to get-rid-of-Japanese-knotweed when used in the summer or early fall, and is not as slow as a homemade duckweed killer you may use in a pond. Japanese Knotweed Expert recommend five treatment visits, conducted over one growing season, and then five subsequent inspection visits over the following 2-3 years.. Each herbicide treatment is bespoke and should consider the proximity of the knotweed to waterways or any non-invasive plants or weeds growing in the near vicinity. The best approach to control is through a combination of cutting and herbicide application. The visceral response a patch of Japanese knotweed evokes in scientists, naturalists and homeowners might surprise you. Encouraging or establishing alternative groundcover provides competition to knotweed, and will enhance the effects of other treatments. Japanese knotweed has come a long way since Philipp Franz von Siebold, the doctor-in-residence for the Dutch at Nagasaki, brought it to the Utrecht plant fair in the Netherlands in the 1840s. The third is the Japanese knotweed herbicides on our list, as it is both Cost-effective and 100% Aquatic approved. WSDA Knotweed Control Program. preventive weed control. View on Amazon. NMISN* advises 3-7 oz/acre and MMSI** uses 6-10 oz/acre. Roundup, Gallup, Landmaster, Pondmaster, Ranger, Rodeo, and Touchdown are all herbicides recommended to kill Japanese Knotweed. 1/2% Cygnet Plus (D-limonene) = 0.6oz/gal spray solution Foliar spray or "cut stem" application (cut down stems and fill the stem cavity with herbicide The best time for Japanese knotweed to be sprayed is when the plant is actively growing as the herbicide we use is a systemic translocating herbicide. At first sight, the plant's small, … Must measure sprayer output to calculate dilution of Milestone; see attached protocol for 6oz/acre rate Yes. However, Japanese knotweed While you could always use a glyphosate herbicide such as Roundup, this can be harmful to the environment. Japanese Knotweed Killer Recipe. The herbicide treatment is most efficient on a warm, sunny day. One example of a cultural control method for knotweed is preventing the spread of rhizome pieces in soil and on excavation equipment. 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