Towards the end of July, three members of the Broadclyst Environment Group spent a Saturday afternoon clearing Himalayan balsam from a stretch of the River Clyst. This meant wading down the river, and we discovered that it gets quite deep in some parts!
Himalayan balsam grows in damp places and is often found along rivers and streams. It is a tall plant, sometimes reaching over two meters in height, with attractive pink flowers—but why go to all the trouble of removing it? The problem is that Himalayan balsam is highly invasive. It is an introduced species that spreads rapidly, crowding out native plants. Left unchecked, it will colonise riverbanks so that nothing else can grow, which is harmful to biodiversity. It is an annual, and when large areas of the plant die back in winter, the riverbank is left bare and susceptible to erosion.
Himalayan balsam has become a big problem along many waterways in the UK and other countries. In our area, the River Culm and the Cranny Brook (the stream that runs through Cranbrook) are badly infested. The Clyst does not have major infestations, as people have been keeping an eye out for plants and uprooting them for some time.
We are hoping that with a concerted effort over the next few years we can rid the Clyst and its tributaries of Himalayan balsam altogether, and we will be getting to work again early next summer. It is important to uproot the plants before they go to seed to prevent any further spread. Also, any plants that are uprooted should simply be left to dry out. They must not be transported away from the site, as it is an offence under the Wildlife and Countryside Act 1981 to move Himalayan balsam plants or cuttings.
If you would like to get involved in any way at all with the efforts to rid the River Clyst of Himalayan balsam, please contact us.
This article was written by Mark Phillips of the Broadclyst Environment Group.