Page last updated at 17:39 GMT, Wednesday, 22 July 2009 18:39 UK

Jams and pie 'solution' for weed

Japanese Knotweed poisoning. Picture: National Trust
Only plants not controlled by herbicides should be used

Harvesting and eating Japanese Knotweed could be the best biological way to control the "nightmare" weed, a woman in Cornwall has said.

Caroline Davey from St Buryan said the shoots of the plant, which taste like rhubarb, can be used in jams, chutneys, crumbles, pies and even cocktails.

Scientists and gardeners have spent years trying to control the weed, which has no natural enemies in the UK.

"We can get rid of it by eating it and it's delicious," Ms Davey said.

The National Trust recently completed a three-year project to clear the weed from a seven-mile (10km) area of the Tregeseal River and the Kenidjack Valley in Cornwall using a herbicide.

It does taste just like stewed rhubarb and knotweed crumble is delicious
Caroline Davey

Japanese Knotweed was introduced to the UK from Asia by the Victorians as an ornamental species, but it has become a major environmental problem across Europe because of its "invasion" of habitats, excluding plants, eroding river banks and damaging structures.

Ms Davey, who runs foraging and cookery courses, said she discovered the benefits of eating it on a US website.

"In Cornwall it's known locally as donkey rhubarb," she told BBC News.

"You can substitute it for almost any rhubarb recipe. It does taste just like stewed rhubarb and knotweed crumble is delicious."

Untreated areas

The plant is recognised for its medicinal qualities in many countries and the edible shoots can be harvested in March and April before the leaves form.

"As an ecologist, I spent many years telling people how to get rid of knotweed," Ms Davey said.

"But it's a huge resource and by encouraging the local community to harvest it and eat it could be the best way of biologically controlling it."

Ms Davey said it was important only to forage for the shoots in areas where the knotweed is not being controlled with herbicides.

She also added that any pickers had to be extremely careful not cause it to grow elsewhere or dump it because it was an offence to spread it under the under the Wildlife and Countryside Act 1981.

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