Invasive species are non-native plants and animals which have been introduced, accidentally or purposefully, into a habitat to dire effect.
They compete with other species for resources. For plants this would include light, air, space. Invasive species disrupt established food chains and habitat structures. Examples of invasive species in the UK are grey squirrels and Japanese Knotweed, Fallopia japonica.
A non-native plant which is invasive is able to establish on many sites and grow quickly. It will disrupt existing plant communities and ecosystems. It may also cause harm to human health and potentially have considerable economic and environmental impact.
The restriction on moving, spreading, selling and treatment of invasive plants is primarily covered under UK law by the Weeds Act 1959 and the Wildlife and Countryside Act 1981.
The most widespread invasive plants, as well as Japanese Knotweed, are Rhododendron, Giant Hogweed and Himalayan Balsam.
Others which are banned from sale include a large number of aquatic plants. For example, Fairy fern, Azolla filiculoides and Parrots feather, Myriophyllum aquaticum.
From Plews Potting Shed
Weeds – Japanese Knotweed and Rhododendron