Knotweed - Ask Extension
I had contacted you recently regarding if I had Japanese knotweed on our property and it was confirmed yes. I was sent an article "How to Battle...
Knowledgebase
Knotweed #871525
Asked June 04, 2024, 12:45 PM EDT
I had contacted you recently regarding if I had Japanese knotweed on our property and it was confirmed yes. I was sent an article "How to Battle Japanese Knotweed and Win" . We have had to cut every 4-5 days. How long to "bake" stalks? How to dispose of bags? "The excess plastic was folded over the pile and secured with stones." We are using lg black contractor bags, is this OK? Someone had told us to just cut, cover with black plastic and cover with bags of soil to weigh plastic down. I really wish this wasn't close to our well because we would have considered chemicals as the cutting every 4-5 days is going to be daunting.
Addison County Vermont
Expert Response
Dear Crystal:
Thanks for undertaking the formidable task of eliminating or controlling the growth of Japanese knotweed on your property. Since it is growing near your well, you understandably do not want to use herbicides. Thus, the best option for you is to cut and smother the area.
Your recent email to us asks two questions: (1) how to dispose of the knotweed stems that you cut and (2) whether there is a way to avoid cutting stems every 4-5 days, which is “going to be daunting.”
Response to question #1, disposal:
You can bring bagged knotweed to the Addison County Solid Waste Management District (ACSWMD) transfer station. We provide a link to the ACSWMD website (https://www.addisoncountyrecycles.org/guide/diseased-noxious-plants-invasive-insects), which states: “If invasive species can not be managed on site, please call ACSWMD at<personal data hidden> before bringing diseased, invasive, or noxious plants to the District Transfer Station so we can determine the best disposal method to prevent seeds, spores or blight from spreading. Loads of diseased, invasive, or noxious plants accepted at the District Transfer Station will either be composted at high temperatures to completely destroy the plants or received as bagged trash and sent to the landfill.” You can bring the knotweed in large paper leaf bags for composting by ACSWMD or in plastic trash bags if the knotweed will be put in the landfill. Obviously, pack the cuttings with care to avoid spreading knotweed segments that could take root.
Alternatively, you can dry out the cut knotweed at your property. In the comprehensive NH publication that we sent to you previously (https://www.agriculture.nh.gov/publications-forms/documents/japanese-knotweed-bmps.pdf), a recommendation (on page 8) is that you “[p]ile all of the stems on an impervious surface such as a tarp, plastic, pavement, etc. so they can dry (after turning brown the stems are no longer viable or a threat).” Once dry, you can burn them or bring them to the landfill.
Response to question #2, cutting:
You state that you “have had to cut every 4-5 days.” I assume that you are speaking of cutting new shoots as they emerge. The resource we sent to you on April 26th (“How to Battle Japanese Knotweed and Win”) suggests cutting the emerging short stalks very two weeks “until the energy storehouse is completely depleted and the plant succumbs,” which can take up to 5 years. This is a daunting task. If you prefer to avoid this chore, we recommend that you follow the guidelines for smothering found at pages 7-8 of the NH publication in the link provided above. We also recommend that you secure mulch from a reputable source to avoid getting mulch that might introduce other invasives to your property.
We hope this answers your questions. We applaud your efforts and wish you success.
Regards,
Pat
Thanks for undertaking the formidable task of eliminating or controlling the growth of Japanese knotweed on your property. Since it is growing near your well, you understandably do not want to use herbicides. Thus, the best option for you is to cut and smother the area.
Your recent email to us asks two questions: (1) how to dispose of the knotweed stems that you cut and (2) whether there is a way to avoid cutting stems every 4-5 days, which is “going to be daunting.”
Response to question #1, disposal:
You can bring bagged knotweed to the Addison County Solid Waste Management District (ACSWMD) transfer station. We provide a link to the ACSWMD website (https://www.addisoncountyrecycles.org/guide/diseased-noxious-plants-invasive-insects), which states: “If invasive species can not be managed on site, please call ACSWMD at<personal data hidden> before bringing diseased, invasive, or noxious plants to the District Transfer Station so we can determine the best disposal method to prevent seeds, spores or blight from spreading. Loads of diseased, invasive, or noxious plants accepted at the District Transfer Station will either be composted at high temperatures to completely destroy the plants or received as bagged trash and sent to the landfill.” You can bring the knotweed in large paper leaf bags for composting by ACSWMD or in plastic trash bags if the knotweed will be put in the landfill. Obviously, pack the cuttings with care to avoid spreading knotweed segments that could take root.
Alternatively, you can dry out the cut knotweed at your property. In the comprehensive NH publication that we sent to you previously (https://www.agriculture.nh.gov/publications-forms/documents/japanese-knotweed-bmps.pdf), a recommendation (on page 8) is that you “[p]ile all of the stems on an impervious surface such as a tarp, plastic, pavement, etc. so they can dry (after turning brown the stems are no longer viable or a threat).” Once dry, you can burn them or bring them to the landfill.
Response to question #2, cutting:
You state that you “have had to cut every 4-5 days.” I assume that you are speaking of cutting new shoots as they emerge. The resource we sent to you on April 26th (“How to Battle Japanese Knotweed and Win”) suggests cutting the emerging short stalks very two weeks “until the energy storehouse is completely depleted and the plant succumbs,” which can take up to 5 years. This is a daunting task. If you prefer to avoid this chore, we recommend that you follow the guidelines for smothering found at pages 7-8 of the NH publication in the link provided above. We also recommend that you secure mulch from a reputable source to avoid getting mulch that might introduce other invasives to your property.
We hope this answers your questions. We applaud your efforts and wish you success.
Regards,
Pat
