Professor Denis Murphy of the University of Glamorgan gaves us a fascinating insight into Invasive Plant Species in Britain: a Historical, Scientific and Socioeconomic Perspective
The talk focussed on the 4 "worst" plants, the infamous Japanese Knotweed (left), Himalayan Balsam, Rhododendron ponticum andGiant Hogweed and explained how they got here, the problems that they cause to people and property and the actions that can be take or are being considered in dealing with them. For instance the Japanese Knotweed Psyllid Aphalara itadori which is being considered as a biological control against the plant.
If you are interested in reading more about non native species you may find this website useful DEFRA GB Non-native Species Information Portal
When it comes to these some of our local ancestors must take some blame ... for Japanese Knotweed the database records Location of first record: Glamorgan
But as Denis reminded us - just 12,000 years ago Britain was an ice covered wasteland. So all our plants and animals are non native if you think long enough