Global spread of invasive Japanese knotweed

Reports indicate the spread of invasive Japanese knotweed in various regions, including South Jersey, United States, and Jelgava, Latvia.

In South Jersey, residents in Gloucester, Atlantic, and Cape May counties have identified plants resembling bamboo spreading through residential yards. The infestation is difficult to manage because the species spreads through underground rhizomes, making simple mowing ineffective. The spread has been linked to neighboring properties where dense vegetation is no longer maintained.

In Jelgava, Latvia, the species has been identified near infrastructure and traffic hubs. Authorities note that the plant is one of the most aggressive invasive species in Europe and poses a risk of economic damage by lifting paving stones and deforming asphalt. The State Plant Protection Service (VAAD) highlights that the plant has been on the European Union’s list of invasive species since June 17, 2025. Local officials are requesting that residents report sightings to assist in mapping the spread.