Revision 0 September 12, 2005 - revision history is at the bottom of document

Invasives Action Plan
for a Japanese Knotweed stand
in the Acton (MA) Wetherbee Conservation Area

Prepared by:
Jim Snyder-Grant
Acton Land Stewardship Committee, and
Acton Conservation Trust


The Wetherbee conservation area consists of two zones – an agricultural field at the intersection of Route 2 and Wetherbee Street, and a forested area with a trail system with one edge along Route 2..

The invaded area covered by this plan is approximately a 40' by 40' section in the forested area, between a trail and route 2.

It is marked as 'Plan Area' in Figure 1, near the end of this document.

Current Conditions

The plan area is an old stone foundation entirely dominated by Japanese Knotweed (Polygonum cuspidatum) that has been repeatedly cut down by the land steward – many times per year for a few years. The area just outside the study area is dominated by invasive bush Honeysuckle and invasive glossy Buckthorn. In addition, goldenrod and Virginia creeper can be found in the nearby under story. Some Sumac is in the mid-layer, and between the plan area and rte 2 there are a few white pine and red oak.

The surrounding area is former orchard now returning to forest on three sides and Route 2 on the remaining side. The agricultural area is 200 yards away, and in the last few years holds “Round-up Ready” corn that is sprayed with Round-Up once or twice a year. There is a small vernal pool between the plan area and the agricultural area, right next to the agricultural area, more than 100 yards away from the plan area. The entire conservation area itself is bounded by roads on most sides, with some intervening private land, some forested, some developed.

Desired Conditions

Although the stand of Knotweed is dense, it is small and contained. With herbicide use and manual follow up, the area can become knotweed free. Sun-loving sand-tolerant native plants could replace it – berry plants would be especially nice since they would provide a good food source for animals. Black raspberry plants are doing well near by. We would like to keep adjacent and nearby meadow areas knotweed-free.

Risks of Taking No Action

Without management, it is anticipated that this Japanese Knotweed invasion would continue to spread beyond the plan area, in to a significantly wider sunny area that surrounds it. The knotweed is unlikely to invade the forested area.

Consistency with Larger Plans

There is no master plan for Wetherbee at this time, nor for the Acton Conservation areas as a whole. The lands are protected by Article 97 of the Massachusetts constitution, so any plans for this area should support “the right to clean air and water, freedom from excessive and unnecessary noise, and the natural, scenic, historic, and aesthetic qualities of their environment; and the protection of the people in their right to the conservation, development and utilization of the agricultural, mineral, forest, water, air and other natural resources”.

I think the main question that needs to be addressed under this standard is whether the temporary poisoning caused by the use of herbicides justifies the gains in ' natural, scenic, historic, and aesthetic qualities'. I believe that the answer is yes. The risks of taking no action are outlined above. The goal of keeping the current mixed meadows intact addresses natural, scenic, historic, and aesthetic concerns. The risks associated with adding new herbicides is low. On the one hand, the land is former agricultural land, and so is hardly pristine – orchards are usually targets of rather intense herbicide activity. The plan area is near currently active agricultural land that makes heavy use of Round-up (Glyphosate). Round-Up breaks down quickly in the environment in to readily bio-degradable components. The exception is near running water, and there is no running water nearby. The nearest vernal pool is more than a hundred yards away. The careful use of roundup will not increase the load of herbicides in the area beyond a few days, and can help prevent the loss of a series of biologically-diverse meadow areas.

Background Information

Good information about Japanese knotweed as an invasive plant can be found on the Invasive Plant Atlas of New England Japanese Knotweed page, including links to further web sites.


  1. Late June – Cut or mow down stalks.

  2. Allow knotweed to regrow.

  3. After August 1 but before first frost, spray knotweed with ROUNDUP [glyphosate (~40%)] @ 2.5 fl. oz./gal.
  4. Hand cut and paint areas of knotweed that cannot be safely sprayed (mixed din with other plants)
  5. Follow-up with hand pulling in the Spring, and a possible extra round of spraying/painting the following Fall.
  6. Planting replacements the Spring after that.


This plan is in four stages: permitting, site prep, herbicide treatment, and manual follow-up


The conservation lands are under the control of the Acton Conservation Commission, and under the administration of the Acton Natural Resources director. The Land Stewardship Committee, charged with care of the conservation lands under the conservation commission, has been very conservative about the use of herbicides, agreeing not to use them without an affirmative vote of the committee. So, I believe the proper course before using herbicides in this area is to write this plan, have it reviewed by the Land Stewards, the Conservation Commission and the Director of Natural resources, and to get a vote from the Commission and the committee, along with the support of the Director.

Site Prep

The spray area will be marked off with colored stakes. The additional areas where plants will be treated individually will be marked off with differently-colored stakes. The staking will be reviewed by town staff.

Herbicide Treatment

Treatment will be done by certified town staff. The outlying areas of knotweed infestation will be hand cut and painted with ROUNDUP [glyphosate (~40%)] @ 2.5 fl. oz./gal. On a subsequent day, the same mix will be sprayed in the main study area.


Cut plants will be bagged and stored on site for at least a month. Then the dead material will be dispersed on site. Sprayed plants will be allowed to die in place, and will not be removed until replacement plants are brought in.


The land steward will look for any possible return of the knotweed and call for follow-up action as needed, including hand-pulling or additional spraying. If funds or donations are secured for replacement plantings, these will be supervised by the steward. A follow-up note describing conditions at the study site will be forwarded to all reviewers of this plan at least once a year until conditions stabilize as a knotweed-free zone.

Open Issues and Next Steps

Plan Review

This plan needs to go through review cycles with the land stewards, the director of Natural Resources, the Director of Municipal Properties, and the Conservation Commission.

Budget and Materials

Need to work with the town to secure certified applicators and supplies and equipment for the spraying

Literature Review:

Need to check and cite additional appropriate sources on knotweed control to help verify that this plan has a decent chance of success.

Permitting logistics:

Need to verify what form the permitting process will take, in consultation with the director of natural resources. We have not done this level of formal review before.

Figure 1: Plan Area 

Figure 1: plan area


This plan is intended as a next step in dealing with many high-priority invasive plant sites in Acton. I look forward to working with town staff and volunteers to make this plan happen. Your feedback on this plan is greatly appreciated.

Jim Snyder-Grant
jimsg 'at' newview 'dot' org
978 266-9409

Revision History

Rev. 0 September 12, 2005. Structurally based on Norway Maple plans, plus a review of the site & a brief look at the literature. Ready for initial review.