• Home
  • About
    • About ISN & FAQs >
      • Projects >
        • Hemlock Woolly Adelgid
    • Our Partners
    • Staff
    • Events
    • Employment
    • Requests For Bids
    • Enews History
    • Donate
  • Identify and Report
    • ID and Reporting Tools
    • Top 20
    • Aquatic Invasives
    • Early Detection Species
  • Resources
    • Education
    • Tool Library
    • Planting Guide/Ordinance Templates
    • Treatment Information
    • Other Information
    • Native Plant Seeds
    • Invasive Species in the News >
      • Nature Change
      • ISN in the News
  • Habitat Matters
    • People
    • Wildlife
    • Michigan
  • Go Beyond Beauty
    • Find Participants >
      • Nurseries >
        • Cyman Gardens
        • Birdsfoot Native Nursery
        • Garden Goods
        • Green Lake Gardens and Goods
        • Greystone Gardens
        • Misty Ridge
        • Northwoods Landscaping & Nursery
        • Pine Hill
      • Landscapers >
        • Cre Woodard
        • Cyman Gardens
        • Designs in Bloom
        • Heritage Landscape Design
        • Inhabitect, LLC
        • Laurel Voran, LLC
        • The Mossy Tree, LLC
        • Northwoods Landscaping & Nursery
        • Old Mission Associates
        • Perennial Harvest
        • Pine Hill
        • Silverman & Company
        • Sustainable Landscape Design, LLC
        • TruNorth Landscaping
        • Wildlife & Wetland Solutions
      • Landowners/other groups
    • GBB Achievement Program
    • Register >
      • Registration Form (Garden Professional)
      • Registration Form (Individual or other org)
      • Start-up Materials
    • News and Updates
    • Ornamental Invasive Species
    • Native Plant Species
    • Participant Signs
    • Japanese Barberry Trade-Up Day >
      • Japanese Barberry Trade-Up Day Event, 2017
    • Japanese Barberry Business Buyback >
      • Japanese Barberry Buyback, 2017
    • GBB Resources
Northwest Michigan Invasive Species Network

Japanese knotweed  control 2014

8/1/2014

 
Japanese and giant knotweed (Polyganum cuspidatum and P. sachalinense) are difficult plants to control under the best of circumstances.  In their home range of Asia, they specialize in re-colonizing and re-sprouting after volcanic lava flows.  In order to do this, knotweeds store energy in underground stems called rhizomes.  This adaptation not only makes them hardy to fire, it allows them to spring up over and over again when cut.  Knotweeds, like mint and bamboo, can also sprout from pieces of stem as small as a few inches long, making tilling and mowing into ways to spread rather than methods of control.
For all of these reasons, chemical control becomes the best bet for killing Japanese and giant knotweeds.  However, their hardy nature means that it may take several years to “conquer” these invasive plants.  The Northwest Michigan Invasive Species Network has been treating knotweeds in high-quality (near waterways) and high-spread-risk (roadsides) areas for three years now, and we’re finally seeing some positive results.


This spring, when the knotweed was about 3 feet tall, we sprayed stands throughout our 4-county service area with Milestone (aminopyralid).  Stands without trees nearby were chosen, as Milestone can harm some species.  Most stands died very soon after, though some sent up a few shoots that were sprayed again in the fall.
In August, we sprayed the remaining knotweed stands with a mixture of Clearcast (imazamox) and glyphosate (the active ingredient in Round-Up) at least 60 days before frost, as recommended by the manufacturer.  As the plants will die back in fall anyway, we’ll have to wait ’til spring to see how effective our treatments were.

Finally, a word of caution.The Northwest Michigan Invasive Species Network state-certifies and trains its crew in appropriate herbicide handling and application.  Though all the herbicides we use are the lowest-risk to human health while still being effective at control and are not restricted-use chemicals, we encourage anyone considering chemical treatment to seek help from a professional in choosing and applying herbicide.  At the very least, reading and following the label and instructions that accompany any herbicide will reduce risk of environmental and health impacts.

    Subscribe to ISN's  monthly enewsletter

    Subscribe
    Picture

    Categories

    All
    Autumn Olive
    Baby's Breath
    Dames Rocket
    Garlic Mustard
    Giant Hogweed
    Go Beyond Beauty
    Habitat
    ID And Control
    Japanese Knotweed
    Native Plants
    Phragmites
    Pollinators
    Treatment
    Update
    Woody Invasives

    Archives

    October 2018
    August 2018
    July 2018
    June 2018
    February 2018
    December 2017
    October 2017
    August 2017
    July 2017
    June 2017
    May 2017
    March 2017
    February 2017
    January 2017
    December 2016
    September 2016
    August 2016
    June 2016
    May 2016
    April 2016
    February 2016
    December 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    January 2015
    December 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    November 2013
    October 2013
    September 2013
    May 2013

Picture

Contact Us

By Phone
231-941-0960

By Email
kgrzesiak@gtcd.org

By Mail
1450 Cass Rd
Traverse City, MI 49685

    Subscribe Today!

Submit
Pleasant Peninsula Design, Habitat Matters 2017 
  • Home
  • About
    • About ISN & FAQs >
      • Projects >
        • Hemlock Woolly Adelgid
    • Our Partners
    • Staff
    • Events
    • Employment
    • Requests For Bids
    • Enews History
    • Donate
  • Identify and Report
    • ID and Reporting Tools
    • Top 20
    • Aquatic Invasives
    • Early Detection Species
  • Resources
    • Education
    • Tool Library
    • Planting Guide/Ordinance Templates
    • Treatment Information
    • Other Information
    • Native Plant Seeds
    • Invasive Species in the News >
      • Nature Change
      • ISN in the News
  • Habitat Matters
    • People
    • Wildlife
    • Michigan
  • Go Beyond Beauty
    • Find Participants >
      • Nurseries >
        • Cyman Gardens
        • Birdsfoot Native Nursery
        • Garden Goods
        • Green Lake Gardens and Goods
        • Greystone Gardens
        • Misty Ridge
        • Northwoods Landscaping & Nursery
        • Pine Hill
      • Landscapers >
        • Cre Woodard
        • Cyman Gardens
        • Designs in Bloom
        • Heritage Landscape Design
        • Inhabitect, LLC
        • Laurel Voran, LLC
        • The Mossy Tree, LLC
        • Northwoods Landscaping & Nursery
        • Old Mission Associates
        • Perennial Harvest
        • Pine Hill
        • Silverman & Company
        • Sustainable Landscape Design, LLC
        • TruNorth Landscaping
        • Wildlife & Wetland Solutions
      • Landowners/other groups
    • GBB Achievement Program
    • Register >
      • Registration Form (Garden Professional)
      • Registration Form (Individual or other org)
      • Start-up Materials
    • News and Updates
    • Ornamental Invasive Species
    • Native Plant Species
    • Participant Signs
    • Japanese Barberry Trade-Up Day >
      • Japanese Barberry Trade-Up Day Event, 2017
    • Japanese Barberry Business Buyback >
      • Japanese Barberry Buyback, 2017
    • GBB Resources