13 July 2012
An appeal has gone out to people who live and work in Dorset, East Devon and Somerset to support an initiative that aims to banish some unwelcome invaders and allow more native plant life back to the banks of the River Axe.
Natural England is co-ordinating a new project to bring three non-native and highly invasive plant species under control before they can overrun the river’s banks, crowd out native species and cause serious soil erosion.
The alien invaders that are being tackled are Himalayan balsam, Japanese knotweed and giant hogweed. When these plants take hold in an area they can quickly create dense monocultures of vegetation that shade out native species. In winter, the Himalayan balsam and giant hogweed die back, leaving the river banks bare and exposing them to a greater risk of soil erosion and potentially more vulnerable to flooding.
Now that the river has settled down again after the recent floods, the project team is asking for local volunteers to join a series of organised visits to areas of the Axe catchment to help control the highly invasive Himalayan balsam. Ideally, the plants need to be pulled up by hand, the stems broken and the plants left to desiccate away from the river to prevent seeds spreading. This approach allows the native plants to remain relatively undisturbed, helping to keep the banks of the river intact and less prone to erosion.
Mervyn Newman of Natural England is organising the ‘bash the balsam’ work and is asking farmers and owners of land along the course of the Axe to support this project by agreeing to allow access to the River and its tributaries for two or three visits from June to August each year until the Himalayan balsam is under control.
Any stands of Japanese knotweed or giant hogweed found along the River Axe that are not already being treated by the County Highways departments will be tackled using professional contractors.
If you would like to know more or would like to get involved as a project volunteer please contact Mervyn Newman on firstname.lastname@example.org.
The project is managed by Natural England and funded through Defra’s Water Framework Directive grant
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Himalayan balsam was first introduced in the 19th century. It is now widespread throughout England and is one of the country’s fastest growing plants, achieving up to 3m height in summer. It grows along river corridors and where the combination of flowing water and the plant’s ‘explosive’ seed heads are a recipe for the plants to rapidly spread over large areas. If left uncontrolled, it can increase river bank erosion and the risk of flooding and, prevent access to the river for recreational activities and harm native vegetation and wildlife. In order for the weed to be banished from the area completely, the plants need to be pulled up by hand before the flowers set seed in July and August. This must be repeated for at least three years because the plants grow from seed each year and it may take this long for the seed bank to be exhausted.
The project team is asking for the help of volunteers to join them on organised visits to the Axe catchment to tackle the troublesome plants. Ideally, the plants need to be pulled up by hand, the stems broken and the plants left to desiccate out of the flood reach of the river to prevent seeds spreading. This approach allows the native plants to remain relatively undisturbed, helping to keep the banks of the river intact and less prone to erosion. Where stands of Himalayan balsam are dense then strimmers will be used to prevent the plants flowering and setting seed.
Giant hogweed was introduced into Britain in the 1890s as an ornamental plant. It escaped from gardens and is now colonising many areas of waste land and river banks. It can grow to 5m high and has large white flowers from which it produces 30-50,000 viable seeds per year. When these seeds fall into water they are dispersed downstream and washed up along the bank allowing the plant to spread and form dense colonies which suppress the growth of native plants and grasses and leave the banks bare of vegetation in the winter.
Japanese knotweed is listed by the World Conservation Union as one of the world's 100 worst invasive species. The invasive root system and strong growth can damage foundations, buildings, flood defences, roads, paving, retaining walls and architectural sites. It can also reduce the capacity of channels in flood defenses to carry water. Japanese knotweed was introduced from Japan in 1825 as an ornamental plant. Its rapid annual growth and relentless spread, allows it to easily overwhelm native plants. Although it does not produce seeds, it can sprout from very small sections of rhizomes.
About Natural England
Natural England is the government’s advisor on the natural environment. Established in 2006 our work is focused on enhancing England’s wildlife and landscapes and maximising the benefits they bring to the public.
We establish and care for England’s main wildlife and geological sites, ensuring that over 4,000 National Nature Reserves and Sites of Special Scientific Interest are looked after and improved.
We work to ensure that England’s landscapes are effectively protected, designating England’s National Parks, Areas of Outstanding Natural Beauty and advising on their conservation.
We run England’s Environmental Stewardship green farming schemes that deliver over £400 million a year to farmers and landowners, enabling them to enhance the natural environment across two thirds of England’s farmland.
We fund, manage, and provide scientific expertise for hundreds of conservation projects each year, improving the prospects for thousands of England’s species and habitats.
We promote access to the wider countryside, helping establish National Trails and coastal trails and ensuring that the public can enjoy and benefit from them.