Himalayan balsam

Himalayan Balsam, also called Indian balsam (Impatiens glandulifera), is a striking tall plant with deep pink/purple flowers and reddish stems that has invaded British watersides and river banks. You can find it along the banks of the River Cerne at Charlton Down in the stretch running parallel to the field of peas. It is a species that was introduced to Britain in 1839 and has now naturalised and become a major weed problem in damp areas.