File:Japanese Knotweed on Bridle Path at Tolpuddle - geograph.org.uk - 905627.jpg

English: Japanese Knotweed on Bridle Path at Tolpuddle. Japanese Knotweed ( fallopia japonica also known as reynoutria japonica also known as polygonum cuspidatum) has been described as the most dangerous weed in Britain. It is an alien species and was imported in the 19th century and now causes huge amounts of damage and eradicates local native species. It is spread by vegetative propagation almost always by mans activities. It can be spread by the transport of only a small fragment of the rhizome (root) It can be seen here on the right hand side in the foreground and in this instance covers an area of 12m X 15m. It has large heart shaped leaves 905628, small white flowers 905631 and hollow bamboo like stems905629. The leaves die back in winter leaving the stems before the new growth starts in spring. This path had recently been cleared possibly resulting in further spread. Excellent information can be found at http://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm#prob