This annual plant germinates in February and March and grows rapidly. It flowers from June to October and produces a relatively high quantity of nectar (6). The flowers are mainly pollinated by bumblebees and wasps, and it has been shown that this introduced species competes with native plants for pollinators. As a result, native species set lower amounts of seed when growing in the vicinity of Himalayan balsam (7).
The generic part of the Latin name Impatiens means impatient, and refers to the means of dispersal of the seed, which is the key to the aggressive spread of this species (6). The seed capsule splits open explosively, scattering the seeds widely. Each plant can produce as many as 2,500 seeds (7), which can stay viable for 18 months and are spread widely in flowing water (6).
Although a popular plant with many, to conservationists Himalayan balsam is a very frustrating species to deal with. Its aggressive nature means that it frequently outcompetes native plants, and causes untold problems in sensitive habitats. Many local Wildlife Trusts organise ‘balsam bashing’ events to control the frequency of the plant in important sites (4).