Monster Weed! Battling Japanese Knotweed in Manistee

Mary Hurley

About 3 years ago, Mary Hurley and her neighbors at Harbor Village in the City of Manistee noticed an unpleasant change nearby. What once was a relatively contained population of phragmites, the invasive wetland plant, was giving way to a rapidly expanding population of Japanese knotweed. This fast growing, invasive woody shrub was taking over the roadsides near their neighborhood and marching across the hillsides.

Mary and the Harbor Village Association got to work researching the problem and soon discovered the Northwest Michigan Invasive Species Network (ISN). Created to help contain and control the most damaging populations of invasive pests in a four county area, ISN began working with the neighborhood group and reached out to the City of Manistee as well.

Team_at_work_cropped_imageIf you encounter Japanese knotweed, it might remind you of the monster alien plant in the movie, Little Shop of Horrors. Japanese knotweed has a powerful will to dominate the landscape.

Imported from Asia, this nonnative plant grows as an incredible rate, forming a dense almost impenetrable wall of wide green leaves and stalks that resemble bamboo, rising 8 to 10 feet high and spreading across the landscape. Knotweed is also a reproducing nightmare, sprouting from even small pieces of the plant stems or roots (called rhizomes). Its spreading rhizomes can penetrate asphalt and crack concrete to send up more plants. It simply out competes native plants, blocking sunlight, but also releases chemicals into the soil that interfere with the growth of other plants.

Katie Grsesiak, Coordinator Northwest Michigan Invasive Species Network

This video helps describe the coordinated effort now underway in the City of Manistee to control and eradicate Japanese knotweed. The work is being supported by citizen groups, the City of Manistee and the Invasive Species Network with funding assistance from the Michigan Invasive Species Grant Program under the Departments of Natural Resources, Environmental Quality, and Agriculture and Rural Development.

Just click on the video window above to watch!


3 thoughts on “Monster Weed! Battling Japanese Knotweed in Manistee

    1. The Northwest Michigan Invasive Species Network recently answered that question on Nature Change Facebook’s page this way: “We use Milestone (aminopyralid) or Clearcast (imazamox), depending on the site, with a non-ionic surfactant and tracer dye. Unfortunately, more well-known herbicides like Round-Up (glyphosate) and Crossbow (mix) don’t do much for control unless you can come back and spray them weekly!”

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