This weed has already caused major problems on other chalk streams in the UK, such as the Dorset Frome. It suppresses the growth of native plants and leaves bare river banks in autumn after the balsam has died back, which are then liable to erosion. In 2010, the legal status of this plant changed, to reflect the serious problem that it is causing. It is now
against the law to plant or otherwise cause this plant to grow in the wild. Therefore, if you are growing Himalayan balsam in your garden and you do not prevent it from spreading into the wild, you are breaking the law.
Himalayan balsam has been found growing at several points along the Chess over the years and was spreading rapidly. Chesham Environmental Group volunteers have done amazing work over the last decade to wipe out large stands by hand pulling the weeds. It is important to deal with Himalayan balsam in Chesham, as this is where the Chess starts, in order to prevent further infestations developing downstream.
Get in touch with the Environmental Group if you would like to find out more, or get involved.
It is important to kill this plant before it flowers, by hand-pulling, cutting, mowing, strimming or by herbicides. If the plant is handled when it is flowering, you are more likely to help it to spread as the seed heads explode showering the area with seeds.