Distribution

Currently, there are few rivers in the UK that have not been colonised by Himalayan balsam and as a result, British rivers have been referred to as “balsam highways”. The Environment Agency has estimated that Himalayan balsam now occupies over 13% of the UK’s rivers. This prolific weed is now naturalized throughout the UK and is present in over 50% of the UK’s 10 x 10km recording squares (see image below). Himalayan balsam is only absent from the higher altitudinal regions of the Lake District and Scottish Highlands.

Geographical distribution of Himalayan balsam in UK and Ireland. Data map © Crown Copyright. All rights reserved NERC 100017897 2004 & NBN Gateway

Geographical distribution of Himalayan balsam in UK and Ireland. Data map © Crown Copyright. All rights reserved NERC 100017897 2004 & NBN Gateway