Japanese Knotweed - Ask Extension
Hi-
I have a fairly large patch of knotweed in my front yard. We built a house recently and are having a lawn installed this summer but from what I...
Knowledgebase
Japanese Knotweed #867520
Asked May 08, 2024, 8:42 AM EDT
Hi-
I have a fairly large patch of knotweed in my front yard. We built a house recently and are having a lawn installed this summer but from what I read, the knotweed is going to continue to be a problem. Are there any programs or resources available to help get rid of it? What would be the best method(s) of removal?
Ottawa County Michigan
Expert Response
The link I provided in the first response is for the West Michigan Conservation Network and they have grant money for invasive plant treatment. I would try contacting Natalie Bekins at<personal data hidden> to see if they can help. If not there is information below on control options.
Physical control.
Repeated chopping or digging may eventually deplete underground reserves thus reducing the competitive edge of Japanese knotweed, however, it is expected to take several growing seasons to achieve eradication. Both root and stem fragments can root and result in new plants, therefore any plant material removed for control should be placed in the trash headed to the landfill and not in yard waste or compost. Mulching is not an effective means of suppressing Japanese knotweed. Mowing is not recommended as it can spread the infestation.
Chemical control.
Repeated herbicide applications of various brush killers, such as triclopyr (Garlon, Pathfinder, Brush-B-Gon), picloram (Tordon, Pathway) or triclopyr + 2,4-D (Crossbow) should help keep this plant under control. Chemical applications can be made to cut stems for more effective treatment of small populations, see herbicide labels for details. Always read and follow the label.
Physical control.
Repeated chopping or digging may eventually deplete underground reserves thus reducing the competitive edge of Japanese knotweed, however, it is expected to take several growing seasons to achieve eradication. Both root and stem fragments can root and result in new plants, therefore any plant material removed for control should be placed in the trash headed to the landfill and not in yard waste or compost. Mulching is not an effective means of suppressing Japanese knotweed. Mowing is not recommended as it can spread the infestation.
Chemical control.
Repeated herbicide applications of various brush killers, such as triclopyr (Garlon, Pathfinder, Brush-B-Gon), picloram (Tordon, Pathway) or triclopyr + 2,4-D (Crossbow) should help keep this plant under control. Chemical applications can be made to cut stems for more effective treatment of small populations, see herbicide labels for details. Always read and follow the label.
