Himalayan Balsam
Britain's worst nightmare
Introduced to the UK in 1839, Himalayan balsam is now a naturalised plant, found especially on riverbanks and in waste places where it has become a problem weed. Himalayan balsam tolerates low light levels and shades out other vegetation, so gradually impoverishing habitats by killing off other plants. It is sometimes seen in gardens, either uninvited or grown deliberately, but care must be taken to ensure that it does not escape into the wild. Himalayan balsam is a tall growing annual, 2-3m (6-10ft) in height. Between June and October, it produces clusters of purplish pink (or rarely white) helmet-shaped flowers. The flowers are followed by seed pods that open explosively when ripe. Each plant can produce up to 800 seeds. These are dispersed widely as the ripe seedpods shoot their seeds up to 7m (22ft) away. The distribution of these from than plant cause more and more to grow as the cycle keeps going on. It is no surprise that it has spread so successfully and is now common all over the UK. None of our native wildlife eats enough Balsam to be able to control it in that way and our native wild flowers can’t compete with it. In the UK it is illegal to plant Himalayan Balsam in the wild or to allow it to spread into the wild. The plant can be eradicated by licenced practitioners using chemical control in certain places, but this is limited to places that are not near rivers, where Balsam often grows The plant is spread in two ways:- The most widespread distribution tends to be by human means where individuals pass on seed to friends
- Once established in the catchment of a river the seeds, which can remain viable for two years, are transported further afield by water where they begin the lifecycle all over again
