• Identification and Control Techniques for Common Upland Invasive Plants in Massachusetts (Chris Polatin, Land Stewardship, Inc.)

• Control Methods for Japanese knotweed (NH Dept. of Agriculture)

• Clean North Controlling Knotweed 

This is the one place where we may actually be able to make progress.  Monitor for new growths and using a shovel dig out the rhizomes being careful to get all of each rhizome and all of the roots and dig three feet deep preferably more.  It is best to dig out a few feet to make sure all material is taken out. 

Monitor the site through the next year. 

Non-herbicide Methods for Subduing Knotweed

While research has not shown that knotweed can be eliminated by non-herbicide methods, there is anecdotal evidence that it can be controlled by intensive non-herbicide methods.

In Vermont, a group of volunteers and towns working together have made progress in subduing knotweed at the Mad River Valley headwaters. This is one of the strongest examples in New England of control by intensive non-herbicide methods. With funding,   the efforts of this dedicated group have been intense by tackling it every three weeks.  Their experience over seven years is discussed in this seminar hosted by the Vermont Land Trust. The video is a must watch for people who want to try this method with the most important information in the Q/A section.

 Untying the Knot: Community-Based Scientific Management of Knotweed in The Mad River Valley

In Shutesbury MA a group is attempting to control small new patches by manually digging the patch, aiming to get the whole rhizome, since splitting the rhizome can generate new growth. For very small patches, digging up all of the rhizomes may be enough to eliminate the plant.

Another possible control is to cover patches with heavy plastic.  The plastic should extend at least 10 feet beyond the patch and should be checked regularly for tears.  This process usually takes five to seven years.

There is a Worldwide Knotweed Support Group based in Great Britain,  where knotweed has been a horrible problem for a very long time.  Worldwide Knotweed Support Group  In England herbicide and soil removal with heavy equipment are used.  However, in the US we are not equipped to move soil since we do not have a good means of disposal.  

Some academic researchers have dismissed physical removal,  digging, pulling or cutting as impractical.

Description of herbicide control with a warning about proper use and restrictions, followed by hyperlinks to resources.

Links to resources

Links to resources