London Train Company to Tackle Knotweed

A London railway operator, Tube Lines Group, has announced plans to eradicate the invasive Japanese Knotweed (Fallopia japonica) from more than 120 sites across London, using the new chemical herbicide ‘Tordon’. If successful, Tube Line will become the first train company in Europe to eradicate the species.

Japanese Knotweed is an invasive, non-native species that was originally introduced to the UK in the mid-19th century. It is notorious for its ability to grow vigorously from tiny pieces of stem or rhizome and can break through drains, brick wall and tarmac as it spreads. Once established, it easily out-competes the vast majority of British flora and can quickly transform the ecosystem it inhabits.

In addition to altering the native flora and fauna, the knotweed can have a detrimental effect on the economy by decreasing the area of land available for agriculture and infrastructure and making certain areas more susceptible to flooding.

Japanese knotweed is difficult and expensive to control using current techniques and an estimated £1.56 billion would be required to eradicate it from the UK entirely. Until now, eradiation programmes have mainly involved digging out the plant or treating it with herbicides, three times a year, over a period of seven years. However, Tube Lines plans to eradicate the knotweed by spraying the herbicide just once a year for two years.

Picloram, the active agent in Tordon, is harmful to plant species other than the knotweed. The US Environment Protection Agency states it is ‘slightly toxic’ to aquatic wildlife, although, the Environmental Protection Agency states it is "practically non-toxic to birds, mammals and honeybees".

If this regime proves to be successful, with minimal impact on non-target species, it may be extended to the remaining London underground services and the national railways.

Original article: Guardian, 6 January 2009; New herbicide offers hope in battle against Japanese Knotweed