Identifying invasive plant species and developing a plan to remove them is a crucial step in creating a Certified Pennsylvania Pollinator Friendly Garden.
Japanese knotweed regrowth, July 2021. Photo taken after cutting, before first herbicide application.
Bordering the site of the Pollinator Friendly Garden Project at the Wyoming County Fairgrounds was an established patch of Japanese knotweed (Fallopia japonica). Reaching heights of eleven feet tall and spreading aggressively through underground rhizomes, Japanese knotweed can propagate and persist with ease. The Pennsylvania Department of Agriculture classifies it as a Class B Noxious Weed, indicating it is widely established in the state and cannot feasibly be eradicated from naturalized areas.
Master Gardener volunteers recall that the 320-square foot area at the Fairgrounds was dense with knotweed for at least seven years. In Summer 2021, Master Gardeners initiated a control and management plan following the recommendations of Penn State Extension.
In the first week of June 2021, the Fairgrounds Maintenance Manager cut the knotweed near ground level and disposed of all plant material offsite. Shortly after, Master Gardeners observed new sprouting of the Japanese knotweed. Approximately eight weeks after cutting, regrown areas were treated with an application of herbicide. Treating the Japanese knotweed regrowth after cutting proved more manageable than treating prior to cutting because the height of the regrowth canopy was shorter and less dense. A second, late-season application of herbicide was completed the first week of October. This second application was critical in carrying the herbicide to the roots and rhizomes. The Master Gardeners have not observed any growth of Japanese knotweed in 2022 and will continue to monitor the area closely.
Read Penn State Extension's recommendations for controlling and maintaining Japanese Knotweed.
The Pollinator Friendly Garden Project at the Wyoming County Fairgrounds is funded in part by the Wyoming County Room Tax Fund and the Endless Mountains Visitors Bureau.
