Gardening the Community: A Discussion of Japanese Knotweed Eradication Methods

The spread of Japanese knotweed from its place of origination in Asian to other parts of the world has become an increasing threat to ecosystems. Currently, Gardening the Community, a sustainable, urban gardening organization centered in Springfield, MA, is experiencing a substantial infestation in their main plot. The main purpose of this project is to compare different methods to control and eradicate the Japanese knotweed on Gardening the Community’s plot as well as, secondarily, to explore beneficial ways Gardening the Community could make use of the Japanese knotweed on its plot. This paper will discuss the methodology, effectiveness, and ecological impact of two options: repetitive mowing and use of the herbicide glyphosate. By synthesizing this information and based of this analysis, the final product produced shall be a recommendation which Gardening the Community can base future actions off of, both in their current plot and in the case of future infestations. Based off of our research, we have determined that the most efficient method of eradication with the least labor cost is the application of glyphosate through stem injection with an estimated 95 to 100 percent knotweed volume reduction after one year of application. Due to Gardening the Community’s pledge not to use herbicides, however, this method was rejected by our client and ourselves. As such, repetitive cutting is our final recommendation as we deem it the second most efficient method, producing a stable decrease in knotweed stem height if more than 4 cuts were applied in one growing season