Stop the knotweeds

In 2012, the Association for the Preservation of Lake Geneva, alerted by the problems caused by the persistent presence of invasive alien species (IAS), launched a major initiative to improve biodiversity along the lake’s shores and its tributaries. ASL conceived an ambitious project, involving the local community, to combat the spread of Japanese knotweed.

These plants pose a real threat to biodiversity because they are not attractive to native wildlife, they outcompete other plants by shading the soil and releasing toxic substances. In our region, these plants are not susceptible to any natural predators or parasites and can spread even from very small fragments. Furthermore, they contribute to erosion of the banks, as their rhizomes do not hold the soil as effectively as native plants. ASL chose manual removal because of its effectiveness and ease of implementation. This method is suitable for all types of terrain, including rocky areas. The campaign takes place annually from April to October, with eight intervention sessions. This protocol guarantees success. Scientific monitoring of the biomass is also conducted. A native plant reforestation program helps to prevent the regrowth of Japanese knotweed.