This paper assessed the effects of species competition between the invasive Himalayan balsam (Impatiens glandulifera) and native species in riverbank habitats. Results from this study suggested that I. glandulifera had a negative effect on above-ground biomass and chlorophyll content in native species. Interestingly, the native stinging nettle (Urtica dioica) may inhibit I. glandulifera in unconditioned soil, especially if U. dioica grows in large single-species stands; however if I. glandulifera is already encroaching on diverse riverbanks, native species are likely to be outcompeted.
Power, G. and Sánchez Vilas, J. (2020). Competition between the invasive Impatiens glandulifera and UK native species: the role of soil conditioning and pre-existing resident communities. Biological Invasions, 22(4), pp.1527–1537.