It is that time of year when our thoughts are turning to summer and all the beautiful and varied floral spectacles it provides in our countryside. Unfortunately, things aren’t always what they seem. For over a decade now large tracts of our lovely countryside have been blighted by alien invaders, one of which is Himalayan Balsam. Native to the Himalayas, it was brought to the UK by Victorian pioneers. Subsequently, it escaped from their gardens and now dominates large areas of England.

This invasive non-native species is now, on a countrywide scale, causing significant damage to the environment and the economy. Unlike some other serious environmental problems such as pollution, the effect of Himalayan Balsam is not a one-off event.  Once it is established, the problems persist and escalate as it spreads further.  If we don't act to control the problem it will continue to escalate at an ever increasing rate, causing us to feel more of the impacts and incur more cost every year. The impact of invasive non-native species collectively is now so significant that they are considered to be the second greatest threat to biodiversity after climate change!

Our local Himalayan Balsam.

How would I identify it? It is an annual plant with pink flowers and a stem that is hollow and jointed that has the ability to produce up to 800 seeds per plant. It grows very rapidly in the spring and summer and can even reach up to 2.5 meters tall. Since it has no natural predators in the UK it smothers and kills off our native species of plants. When it dies back in the winter, it leaves the ground bare and vulnerable to erosion i.e. loss of top soil and increased rates of erosion of river banks. The cycle is repeated the following spring over an ever increasing area unless it is controlled. The erosion also reduces fish numbers in our rivers and increasingly pollutes our lakes.

Over the last ten years massive efforts have been made by organisations including the National Trust, Lake District National Park, Natural England and the Environment Agency above Ouse Bridge. Their dedicated work has now significantly reduced the numbers of these plants locally. They have now reached the stage where we the public now have an opportunity to eradicate this plant from our valley. Many groups of volunteers have been recruited to act as ambassadors in the community. They have adopted various stretches of rivers or lake shore in order to pull up the menace before it can seed. Organizations such as the Lions, who have adopted the River Greta in Keswick from the Forge Bridge down to where the Greta joins the River Derwent, are providing additional support for volunteers over the summer months should their adopted stretch have too many plants to control.

The more ‘balsam bashing’ volunteers there are, the more likely we are to eradicate this plant from the Derwent catchment. Your involvement in this community project would be fantastic. If you are interested in helping either to identify it or pulling it out on your walks please contact - Ian Creighton of the Derwent Rivers Trust by email at

May 2011