Himalayan balsam is an invasive non-native plant that is found along many rivers and waterways in the UK. It was introduced in the 19th century before spreading rapidly into the wild and is now the dominant species along the river bank in many areas of London. It has a very effective seed dispersal mechanism as it has “exploding” seed pods allowing each plant to spread 600 seeds up to 5 metres from the plant. These seeds can then be transported downstream and colonise new areas quickly.
These plants are are a problem as they grow in very dense stands and suppress the growth of native vegetation. In winter this becomes an issue as the plant dies back and leaves the banks vulnerable to erosion, with increased silt inputs potentially degrading spawning habitats for fish.
It is therefore important to manage Himalayan balsam to prevent it getting out of control along our rivers. We’ve been working with The Royal Parks and The Friends of Richmond Park to clear the restored sections of the Beverley Brook of litter and Himalayan balsam.
Last month, a group of dedicated volunteers worked hard to rid the entire 600 metre stretch of river of this troublesome plant as well as removing several large sacks of litter. Well done to everyone who came along to help.
This work will continue each year to ensure the plant does not return. It also ties in with our wider work to manage invasive plants as a catchment scale along the Brook. For full details on this problematic plant check out our web page here.