Himalayan balsam on the River Don, towering over a boy who is helping to demolish it
(Click photo to enlarge)
Holywell Dene could get like this !
How did it get here? It comes from the western and central Himalayas, and was introduced into Britain as an ornamental plant by the Victorians. It has run riot in the Tyne valley and many other places, forming dense stands of 8-foot-tall plants that crowd out all other plants on the river banks.
Seeds. The flowers turn into seed pods which go “pop”, throwing the seeds up to 7 metres (23 feet)! These grow into new plants the following year. Some seeds get washed downstream and start new colonies. The plant dies off in the winter, leaving river banks bare and vulnerable to erosion.
Roots. The roots are insubstantial, and the plant needs wet or moist soil. The roots are not a problem as regards spread. However the stems can root in – which means plants that have been pulled out can re-root.
Nectar. Himalayan balsam flowers produce large amounts of nectar. The plant even has glands on the stems that produce even more nectar! In fact, it produces so much nectar that it can attract bees and other pollinators away from native plants – bad news, bearing in mind the recent decline in pollinator numbers.
Image courtesy of Greentree Landscape Management Ltd, a Sheffield landscape management company who do Himalayan balsam clearance work.