ONE of the most invasive plants in Britain is taking hold along the picturesque River Tavy and causing a serious threat to native flora and fauna. Japanese Knotweed is spreading, obliterating views of the river and killing off native species as it rampages through the riverbank. Local resident and countryside lover Teresa Hughes walks her dog along the river in the Meadows most days and has seen the plant multiply. She said: ?I noticed a tiny bit of knotweed last year, but this year it has really taken hold. ?It grows so well and so thick that soon you will not be able to see the river at all and there will be no blackbirds or thrushes.? Mrs Hughes lived in Wales for 20 years where she saw large areas of land taken over by Japanese Knotweed. ?Landowners had to call in Japanese Knotweed experts to try and control it. ?It?s like an advancing army and can spread seven metres in a year.? It is an offence to ?plant or otherwise encourage the growth of? Japanese Knotweed under the Wildlife and Countryside Act 1981. Together with Giant Hogweed, the plant is rapidly becoming a serious problem in a range of habitats, particularly roadsides, riverbanks and derelict land, displacing native flora and causing structural damage. Cut knotweed material and soil containing rhizomes must be disposed of as controlled waste if it is to be removed from the site of origin. Mrs Hughes said the rhizome network underground may extend to a depth of three metres and seven metres horizontally around a clump. ?The perennial plant dies back in October, leaving dead brown hollow canes, then in late March it will start to throw up new shoots ? two metres by the end of May and three to four metres by the end of June,? she said. The leaves of the Japanese Knotweed are light green and heart shaped and in late August the plant produces small clusters of cream flowers. Deputy works superintendent for Tavistock Town Council Ken Sedgman said the authority had set up a programme to try and eradicate the weed from the riverbank. ?Because it is right by the river we cannot spray it so we have to stem-inject it with herbicide,? he said. Mr Sedgman said the best time to tackle the problem was in late summer and early autumn. ?We need to tackle it soon because we realise we cannot leave it too much longer. We did some stem injections last year but the problem is it grows everywhere. ?It?s the devil?s own job to get rid of it but that is what we are trying to do.?
