Himalayan Balsam (Impatiens glandulifera) Some facts about Himalayan balsam: Arrived UK in 1839. Annual - grows 2m typically on river banks. Suffocates native plants if unchecked. Disperses approx. 800 seeds which can last 2 years. Can be treated by spraying, pulling or cutting. It has very poor root growth so causes increased erosion to river banks when it dies back in the winter.