We review recent research into the impact of bitou bush (Chrysanthemoides monilifera spp. rotundata (DC.) Norl.) on coastal ecosystems which suggest this weed is having widespread impacts on ecosystem services, flora and fauna. Increased decomposition rates and altered nutrient cycling accompany changes in plant community structure and composition. Changes in invaded habitats influence invertebrate and bird assemblages. We summarise research that shows that the establishment phase of seedlings is the key phase where bitou bush outcompetes native species through both resource and interference competition mechanisms.