Himalayan Balsam may seem to be an attractive purple flowered plant which is in full display over the summer months, mainly along river banks and waste land. However, unfortunately it is a non-native, invasive plant and can quickly smother other vegetation. After smothering other vegetation around it, Himalayan Balsam plants die back in the winter leaving bare soil. Often, rivers flood and can then wash the soil away which causes erosion to the riverbanks. This erosion can lead to a build-up of sediment within the rivers which can have a detrimental impact on the wildlife living in the rivers. Each plant can produce up to 800 seeds – these explode from the pod when ripe and can spread up to 4 metres from the plant, often into nearby watercourses which further helps the spread of the seeds. Therefore, Himalayan Balsam is highly invasive and can have a detrimental impact on the native flora along the riverbanks and also the wildlife living in the rivers.
Over the last 10 years, the Clwydian Range and Dee Valley AONB have been working in partnership with Flintshire County Council, North Wales Wildlife Trust, Natural Resources Wales and Wildground to eradicate Himalayan Balsam along the River Alyn from the source in Llandegla to Mold.
We primarily control Himalayan Balsam by hand pulling with groups of volunteers but we do use contractors as well to treat denser areas. When pulled, the Himalayan Balsam needs ‘scrunching’ up so that it is completely destroyed and we then put it into small piles along the riverbank which decompose quickly. It needs to be pulled before it goes into seed so most of the work needs to be done before August. However, plants can still be found coming into flower as late as November so it is important to keep re-walking sections to check for new growth.
Over the years we have seen a huge reduction in plants and it is hoped that the first 10 miles of the River Alyn will be Himalayan Balsam free. At one point, this stretch of the river was abundant with Himalayan Balsam. However, we have now managed to minimise it to just a few hotspot areas which we are focussing on this year. After this, we will then be focussing our efforts on reducing the amount of Himalayan Balsam further downriver.
If you would like to take part in any of the Volunteer days this summer focussing on Himalayan Balsam, please get in touch with John Morris at Loggerheads Country Park (01824 712757).