Parrot's feather (Myriophyllum aquaticum) - Non-native Species
Parrot's feather is native to Central and South America and has been grown in water gardens in the UK since 1878. First found in the wild in 1960, it does not spread by seed (as all the plants in the UK are female) but is able to re-grow from small fragments of parent plants. This method of dispersal combined with a relative lack of natural predators means that the species can spread rapidly through a water system. Parrot's feather can cause flooding by blocking watercourses and drainage channels. It also out-competes native species, reducing overall biodiversity.