ALTHOUGH it hails from a remote region of the western Himalayas, this plant now looks entirely at home on the banks of English rivers. Brought to the UK in 1839, it quickly escaped from Victorian gardens and colonised river banks and damp woodlands. Now it is spreading across Europe, New Zealand, Canada and the US.
This is Himalayan balsam (Impatiens glandulifera), also known as policeman’s helmet because of its resemblance to the British bobby’s headgear. But don’t be fooled by its prettiness – this is one of the most aggressive weeds in the world.
Why so prolific? In the Himalayas the…
