Himalayan or Indian balsam (Impatiens glandulifera) is an annual herb and was introduced to Britain in 1839. Its common name is “Policeman’s Helmet” due to the shape of the flowers. Other balsams include Orange balsam (Impatiens capensis – from North America) and the rare Touch-Me-Not balsam (Impatiens nolitangere – native to British Isles).
Himalayan balsam grows up to 3 metres high with a hollow and bamboo-like stem, pink-red to green in colour with green vertical grooves. Because of the colour and type of the stem it has occasionally been mistaken by the uninitiated for Japanese knotweed. Leaves are long, slender and shiny, with serrated edges and are dark green in colour. Himalayan balsam produces purplish to pale pink flowers in mid-late summer. On rare occasions flowers are white. Seed pods are carried on long stalks between June and October and resemble an elongated pear. When disturbed or touched they split, resulting in seeds literally exploding from the plant. Each plant can produce around 2,500 seeds that can be propelled up to 7 metres in distance. Seeds that enter watercourses can travel over 10 km before germinating in the spring. The plant is mainly found on riverbanks and damp ground. It spreads predominantly along watercourses but is also spread by human interaction.
