Himalayan Balsam

Himalayan Balsam, Copyright Allen Beechey 

Himalayan balsam rapidly takes over riverbanks and areas of damp ground. It can grow up to 3 metres tall, with pinky-red stems and spear-shaped, dark green leaves with serrated edges. Flowers are pink and slipper-shaped and appear from June to October. For assistance with identifying Himalayan balsam, you can download a leaflet from DEFRA (PDF, 5.1 MB - this large leaflet may be slow to download).


 
Himalayan balsam flower - courtesy of Allen
Beechey, Chilterns Chalk Streams Project


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 is growing at several points along the Chess, and is spreading rapidly. Most stands are small enough to be easily controlled by manual methods at present, and should be dealt with now before the problem gets out of control. 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. Chesham Environmental Group hold regular working parties through the summer months to hand-pull local infestations. 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. Download a leaflet on how to identify and control Himalayan balsam (PDF, 55 KB).
 
Chesham Town Council is working with the Chilterns Conservation Board to map this weed. If you have seen these plants growing in Chesham, please contact Kathryn Graves on policy@chesham.gov.uk.
 
Balsam Invasion on the River Frome, by Martin de Retuerto, Wiltshire Wildlife Trust
 Above image: The Himalayan Balsam invasion on the Frome has wiped out native vegetation