Britain’s most destructive plant which has the potential to damage a property’s foundations and cause its value to drop by tens of thousands of pounds has been found around some of Hampstead’s most exclusive homes.
Japanese knotweed is spreading rapidly along the footpath which links Redington Gardens and Heysham Lane – just a stone’s throw away from properties owned by London’s rich and famous, including TV presenter Esther Rantzen, footballer Thierry Henry and TV presenter Melanie Sykes.
The bamboo-like plant, which grows a rate of 10cm a day, has extensive, deep roots which can compromise the structure of buildings, capable of forcing its way through floorboards and brick walls.
So aggressive is the plant, a number of banks refuse to lend mortgages on properties which have Japanese knotweed found in the surrounding area.
Matthew McCarthy, 43, from Frognal, said he spotted the plant growing when he was taking his children to Spedan Close play area two weeks ago and reported it to Camden Council.
Hundreds of Japanese knotweed plants standing at more than two metres tall can now be seen along the footpath and in the woods in Branch Hill, just several hundred metres south of Hampstead Heath. The weeds have also spread into the gardens of two neighbouring properties.
Film actor and nearby resident Tom Conti visited the site this week. He said: “It’s like the Japanese secret weapon. It’s innocuous looking, which is part of the danger.
“It’s worrying when it proliferates at this rate. It’s colossal – ‘The Day of the Triffids in Hampstead’.
“Everybody should be worried about their property. You would have thought something would have been done by now.”
In 2011, a couple’s Hertfordshire house which was invaded by Japanese knotweed was devalued from £305,000 to £50,000. They were advised to demolish their home and remove the soil.
Mark Harris, chief executive of mortgage broker SPF Private Clients, said: “If Japanese knotweed is found, it needs to be investigated and can raise alarm bells with lenders. It doesn’t have to be a deal breaker but there are two or three banks which will not lend if it is found.”
The weed was brought over to Britain as an ornamental plant by the Victorians and spreads through its crown, root and stem segments as opposed to its seeds. It has no natural predators in this country.
Camden Council confirmed that Japanese knotweed has been located on public land in green areas around Redington Gardens and said the plants would be treated this week.
Under the Environmental Protection Act, the weeds have to be disposed of by a specialist contractor within licensed sites. It is a criminal offence if a land owner who finds the weed growing on their property fails to remove the plant under these rules and could lead to prosecution.
Cllr Tulip Siddiq, cabinet member for culture and communities, said: “Japanese knotweed is one of the worst invasive species, with a root system that damages buildings, paving and walls.
“We take reports of it very seriously. Council officers inspected the site immediately and ensured specialists would take swift action to treat the problem so that it does not have the opportunity to spread.”
The City of London confirmed there had been no Japanese knotweed found on Hampstead Heath but it has grown there in the past.
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