A bag, gloves, a garden hook: early digging out,a gentle technique against the invasion of rivers by Asian knotweed

Abstract

During flood periods, the erosion of the banks invaded by Asian knotweed contributes to the spread of plants along the rivers. Indeed, vegetative fragments are uprooted, transported by the water and then deposited a little further downstream, where they can give rise to new plants. Tests have shown that these propagules are often buried under thin layers of sediment and can be easily removed with simple hand tools in the first year after dispersal. Based on these initial findings, annual walking campaigns known as "early digging" were set up to detect and quickly eliminate these new plants. Feedback from this management carried out along small and medium-sized fast-flowing rivers and around a lake shows that this gentle technique has the advantage of being both inexpensive and effective in slowing the spread of Asian knotweed.