Battle to stamp out balsam as invasive plant spreads its roots
Pink ornamental brought in by Victorians destroying habitats and causing flooding across Britain
THE spread of invasive Himalayan balsam is now so bad that drivers who see it growing along roadside verges are being encouraged to stop and pull it out or contact their council immediately.
The attractive pink plant was introduced to Britain as an ornamental in 1839, but soon found its way out of gardens and into the countryside where it has been spreading rapidly since.
Until now, it has stuck largely to the banks of canals and rivers, but increasingly it is moving into verges and hedgerows where it has a greater chance of spreading because of walkers and traffic.
According to the Royal Horticultural Society, each plant can produce 800 seeds a year and their explosive seedpods can fire them up to 22ft away. In addition, bees are attracted to the flowers and can spread the seeds widely.
The plant, which can grow up to 10ft high, has heavy foliage and can crowd out native species. When it dies back it leaves banks bare, so they erode and crumble, leading to flooding. The loss of native species also means a loss of habitats for wildlife in winter.
Louise Wooley, an ecologist who organises annual “balsam bashing” events in Devon, said: “Every year Himalayan balsam grows exponentially and it’s really reached a point where people are starting to notice it everywhere and it will reach peak catastrophic levels if we don’t do something about it. It’s an annual plant so if you snap the plant and just leave it in a pile it will die off quickly before it can seed. We need more people to be getting out there and getting it out of the ground.” A recent study by Durham University found that Britain is one of the worst countries in the world for invasive species, with Himalayan balsam cited as a significant problem.
This month, local groups across the country have been scouring riversides and road verges to remove the plant. The ninth annual Three Rivers Clean Up for the Ravensbourne, Pool and Quaggy rivers in south-east London, a three-week blitz of waterways in the capital, has just finished.
Similar projects are taking place in Devon, Yorkshire, Shropshire, West Sussex and Cumbria.
“It needs to be cleared away every year,” said Paul Greaves, a river action group co-ordinator at Eden Rivers Trust in Cumbria, a county which is prone to flooding during wet weather. “It’s important that we keep on top of the problem.”
Dr Trevor Dines, a botanical specialist at the charity Plantlife, said if people see the plant they should contact their council immediately, as it seemed to be spreading “as if it’s adapting to drier soils”.