Himalayan Balsam is an invasive weed introduced to the UK during the Victorian era. Balsam has spread rapidly along streams and rivers and has now become a serious problem on many of the UK’s river valleys and the Churnet is no exception.
This weed outcompetes many of our native plants particularly in rare wet woodland habitats. The flowers are so nectar rich that they draw native bees away from native plants reducing their ability to reproduce, meanwhile the balsam continues to thrive. Balsam is also an annual plant meaning it dies back in winter and this causes problems as winter rain storms then wash away bare river banks causing erosion and meaning excess amounts of sediment enters the rivers and streams. This sedimentation can affect the wildlife in the river and can contribute towards flooding as the natural profile of the river changes increasing the risk of it bursting its banks.
It is therefore important to control Himalayan Balsam. This is usually done by pulling it up by its roots – this is quite easy because the plant is an annual. Balsam can produce roots from its stem after it has been pulled so it is important when pulling it to tear the plant up to break all the fibres in the stem and then to stack it in piles so that any regrowth is contained in one manageable location.
After the plant flowers it produces spring loaded seed pods that if disturbed can fling the seeds up to seven metres. Therefore, pulling it after these seed pods have matured can do more harm than good so it is important that people who pull it check for seed pods first. After seeds have developed the plant should be left. Because the seeds can spread so far it’s also important to pull individual plants that have managed to spread away from the river to stop the spread travelling any further.
For further information there are a variety of sources on the web i.e. http://www.derbyshirewildlifetrust.org.uk/sites/default/files/files/DWT-...