What is Himalayan balsam?
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 balsam 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.
What are the dangers?
Himalayan balsam presents no physical danger to either humans or animals. It does, however, provide a significant ecological impact since it grows in dense stands that suppress native grasses and other flora. In the autumn the plants die off leaving riverbanks bare and highly susceptible to erosion.
There are no legal issues relating to Himalayan balsam.
Himalayan balsam control & eradication
Relatively weak roots means the plant can be pulled or dug up before the seed pods are produced. Digging operations will need to be carried out for at least two years as seeds can remain viable for several years. Chemical control is also possible, though Environment Agency consent will have to be sought prior to chemical application to plants on riverbanks. Japanese Knotweed Ltd always liaise closely with Environment Agency officials in such circumstances. It should be noted that if Himalayan balsam still exists upstream then control will never be fully effective.
Himalayan Balsam Identification
These images will help identify Himalayan balsam at different stages of it's growth cycle.