As part of London's
Capital Clean-up sponsored by
Proctor & Gamble, the Environment Trust teamed up with the
Friends of the River Crane Environment and
The Conservation Volunteers (formerly BTCV), to try and reduce the abundance of the invasive plant Himalayan balsam from along the River Crane. Left to its own devices, Himalayan balsam outcompetes and overshadows native plants, and deprives them of pollinators. While it is unlikely that Himalayan balsam can be eradicated, its prevalence can be reduced by hand weeding. Groups around the country, including the Quaggy Waterways Action Group (QWAG) in SE London have had success in controlling Himlayan balsam, and new initiatives are taking off such as on the River Test in Dorset and Hampshire
http://www.hwt.org.uk/news.php/665/test-news Thankfully, Himalayan balsam seeds only remain viable for about 18 months, and viable seeds will normally germinate in the first season. This means that it should, in theory, be possible to elimiate this plant from a catchment, given sufficient volunteer effort. However, it only requires one plant to release its 800 seeds (30,000 seeds per square metre in dense stands), to undo all the good volunteer work.
If you missed out on the Big Balsam Bash, there's still a chance to do your bit. Our monthly event on May 26th (10.00-1.00) will be our very own balsam bash by the River Thames at Ham. Meet at the Ham House car park. It'll be muddy, so wellies are recommended.
Balsam bashers get stuck in amongst the stinging nettles.
The balsam has been slow to get going this year, but it'll soon tower above the nettles.
Himalayan balsam - Impatiens glandulifera (left) seen growing alongside orange balsam - Impatiens capensis, a smaller species native to North America, but seemingly increasingly common on British river banks.
