Invasive weed infestation is cleared from Wheathampstead river

A team of volunteers have spent a day pulling pesky Himalayan balsam from the banks of the River Lee in Wheathampstead.

The plant, which was introduced to the UK in 1839 but is now considered a weed, grows fast and tall and can be a huge problem for native fauna. Left untamed, the invasive plant, originally from the western Himalayas, will spread downstream and take over the native species’ habitat.

A variety of twee nicknames - policeman’s helmet, bobby tops and gnome’s hatstand - mask the plant’s aggresive methods of seed-dispersal. A soft touch to the pressurised pod will cause a minor explosion, scattering the seeds up to seven metres.

Due to the plant’s tendency to die back during the winter, erosion to the river banks is another unwelcome side-effect.

Anna Jarmolinska, environment and sustainability advisor at Affinity Water, said: “We were really pleased to work together with our strategic partners at Herts and Middlesex Wildlife Trust. We are committed to reducing the impact of our operations on sensitive habitats such as chalk streams and to maintain flow in our local rivers.”

The River Lee is one of only 170 chalk streams, most of which are found in the south-east of England. Pulling the Himalayan Balsam before it blooms each summer is key to preserving the river’s special wildlife and geology.

David Johnson, from Hertfordshire Living Rivers, said: “It was great to see so many willing volunteers.

“By pulling some of this non-native invasive species from the banks of this rare chalk river, the volunteers will be helping protect the river for future generations.”