An invasion of Tavistock river bank by a fast speading alien plant has been tackled by a dedicated clearance team.

The pink-flowered Himalayan Balsam is alien to the UK and, as a fast-spreading non-native plant, needs to be managed to avoid harming the existing ecology. It is even a threat to land and other property because of its pervasive growth.

Landowners have a legal obligation to manage and control non-native plants because they can damage native plant and wildlife and soil.

Tavistock Town Council is clearing about 50 feet of River Tavy bank on Market Road where the plant, which grows up to six feet tall, has colonised the steep riverside in large patches of dense growth.

Himalyan Balsam has a strong balsam or fir or resin type of smell and originates from the Himalayas and loves soft non-rocky waterbanks, but can also be found in moist and semi-shaded areas and thin woodlands.

Its main threat to the UK ecology is how it spreads rapidly through the ejection of as many as 800 seeds for up to seven metres, taking over large areas to establish dominance to the exclusion of all other native wild plants during the spring followed by flowering from mid-July onward.

A council spokesman said Himalayan Balsam is a non-native invasive plant listed in the Wildlife and Countryside Act 1981 and the council seeks to adhere to government guidance in its management and control.’

One of the management difficulties to overcome in getting rid of it permanently are the long-lived seeds which can overwinter undetected in the soil for two years before germinating in the spring.

The Government guidelines in treating invasive non-native plants, such as the well known Japanese Knotweed, include stopping them from spreading and causing a nuisance or damage to other land or property. If landowners fail in this duty, they are warned they could be responsible for any damage they cause and may be prosecuted.

There is concern the Himalayan Balsam in Tavistock could even grow through the old riverside granite wall which prevents access to the fast flowing river.

In order to be effectively removed without inadvertently spreading the plant through dispersing seed and roots, the council is believed to be laying the plant down on wooden pallets to die, before removal.

Safe methods of disposal include chemical spraying, pulling or digging dead or dying plants, cutting back plants, burying or burning.

After treating invasive non-native species, landowners are told they should re-establish native plant species. This will help to reduce soil erosion, provide competition and control them to prevent further invasion

The unwelcome horticultural guest is not poisonous, is loved by bees and fed on by sheep and cattle in the UK, while two species of aphid are known to feed on the plant. It is also a common food for the Elephant Hawk-moth.