Evaluation of Imazapyr, Glyphosate, and Triclopyr for Japanese Knotweed (Polygonum cuspidatum Sieb. The herbicide treatment is most efficient on a warm, sunny day. See our Written Findings for more information about Japanese knotweed (Polygonum cuspidatum). Japanese Knotweed Killer Recipe. 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 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. preventive weed control. It is native to Asia, and was originally introduced to the U.S. as an ornamental in the late 1800's. The best time to spray the leaves of Japanese Knotweed with herbicide is late summer or early autumn. Encouraging or establishing alternative groundcover provides competition to knotweed, and will enhance the effects of other treatments. The most common and preferred treatment method is a herbicide treatment. A late spring/early summer treatment followed by an early fall re-treatment is needed. 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. WSDA Knotweed Control Program. The best approach to control is through a combination of cutting and herbicide application. By being a cost-effective way of controlling knotweed, the gallon herbicides can effectively cover an area of more than 25,000 square feet. The visceral response a patch of Japanese knotweed evokes in scientists, naturalists and homeowners might surprise you. View on Amazon. Control Introduction Japanese knotweed is a federally listed invasive perennial native to Asia (National Agricultural Library 2004). Managing Japanese Knotweed Japanese knotweed (Polygonum cuspidatum) is an imposing herbaceous perennial that is commonly called 'bamboo'. 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. One example of a cultural control method for knotweed is preventing the spread of rhizome pieces in soil and on excavation equipment. It grows in dense patches to heights of 10 feet, on sites ranging from strip mine spoil to shaded streambanks. However, Japanese knotweed One popular Japanese Knotweed herbicide treatment method is the leaf application of herbicides, also known as foliage spraying. & Zucc.) Must measure sprayer output to calculate dilution of Milestone; see attached protocol for 6oz/acre rate Yes. Roundup, Gallup, Landmaster, Pondmaster, Ranger, Rodeo, and Touchdown are all herbicides recommended to kill Japanese Knotweed. Report on knotweeds from the book "Weed Control in Natural Areas in the Western United States" Cowlitz County NWCB Fact Sheet on Japanese knotweed. The third is the Japanese knotweed herbicides on our list, as it is both Cost-effective and 100% Aquatic approved. The Process. 14oz/acre for Japanese knotweed. This particular type of herbicide poisoning treatment is the ideal solution for treating large and small areas infested with Japanese Knotweed. At first sight, the plant's small, … This herbaceous plant (sometime referred to … NMISN* advises 3-7 oz/acre and MMSI** uses 6-10 oz/acre. They are all glyphosate-based herbicides and will kill the troublesome weed. 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. 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