Invasive Japanese Knotweed has taken a hold in the green area between Watchbell Street and South Undercliff and is proving impossible to get rid of.

Japanese knotweed is a large herbaceous plant native to eastern Asia in Japan, China and Korea.

It has been classified as invasive in several European countries and is listed by the World Conservation Union as one of the world's 100 worst invasive species.

It can force its way through tarmac and the floors of houses and its roots can survive temperatures of minus 35 degrees.

It is illegal to plant knotweed in your garden or in the wild and is classified as controlled waste when it comes to disposing of the plant.
Japanese knotweed was first introduced to Europe and North America in the late 19th century for ornamental use, to prevent soil erosion, and as a forage crop for grazing animals.

Royston Godwin, of Rye Allotment Association, said: "This plant is a nightmare. It spreads like wildfire and chokes all the native plants and flowers.

"It is everywhere on the bank below Watchbell Street and we are worried it will spread further.

"Once it takes a hold it is very difficult to get rid of."

The success of the species has been attributed to its tolerance of a very wide range of soil types. It's roots can survive temperatures of -35 °C and can extend 23 ft horizontally and 9.8 ft deep, making digging it out extremely difficult.

A spokesman for the Depapartment of Agriculture and Rural Affairs (DEFRA) said: "This is a large vigorous weed that appears to have no natural enemies in Britain.

"It can colonise most habitats and is regarded as a troublesome pest in many parts of the country because of its rapid invasion and domination of habitats, which results in the exclusion of other plants.
It can damage property by growing through tarmac or even the floors of houses.

"The species also causes problems in terms of flood management. It increases the risk of riverbank erosion when the dense growth of the plant dies back in the autumn exposing bare soil.

"It can also create a flooding hazard if the dead stems are washed into the streams and clog up the channel. A fragment of root as small as 0.8 grams can grow to form a new plant.

"The Government is aware of the problem.

"Both the Police and local authorities have enforcement functions for the 1981 Act. In addition, Japanese knotweed is regarded as controlled waste and has to be disposed of at licensed sites or by burning on site."

The plant does have some fans though. It is said to be valued by bee keepers and its roots are used in traditional Chinese and Japanese herbal medicines as a natural laxative.