Weed killer

Find out how to combat the biggest natural threat to the UK's countryside - Japanese Knotweed

The weed is a non-native species that was first introduced to the UK as an ornamental plant by the Victorians- it's now No 1 in the Environment Agency's Top 10 most invasive species in Britain and is causing problems not just in Cornwall.

The removal of knotweed from the 2012 Olympic site in East London could cost hundreds of thousands of pounds.

Planting or dumping it can lead to two years in prison, a large fine, or both, under the Wildlife and Countryside Act 1981.

Why is it such a problem?

• The weed can reach up to 12 feet in height and its roots can stretch 10 feet down into the ground.
• It currently occupies most regions of the British Isles except Orkney.
• It's thought the cost of removing knotweed from Britain completely would be more then £1.5 billion.
• Because it doesn't originate from the UK it doesn't compete fairly with our native species and can spread unchecked.
• Once established the weed shades out native plants and drives out wildlife. Although it's not toxic to humans, animals or other plants it offers a poor habitat for native insects, birds and mammals.
• The weed can severely damage buildings and roads and it can push through tarmac and concrete paving.

How do you get rid of it?

• Knotweed is one of the hardest weeds to remove - it is almost impossible to dig out because every piece that's missed will form a new plant.
• It can regenerate from a missed or dropped segment as small as a drawing pin.
• The new procedure being used in Cornwall will see the stems of the weed hacked down and then a herbicide will be injected into each stump.

Knotweed is proving a problem all over the UK, but particularly in Cornwall and Wales, because of the climate and the fact there are large areas of unmanaged land.

The project underway in the Tregeseal River is expected to take up to three years to complete.