Japanese knotweed: the scourge that could sink your house sale

Lisa Campbell in the Guardian (UK): Two weeks before he was due to exchange contracts and move into a new home, Peter Gingell received a call from his estate agent saying the whole thing was off. His buyers had pulled out, his chain had collapsed and his dream home was just that. The reason? A 3cm-high weed in his back garden.

"When I was told, I thought it was a joke," says Gingell. However, this wasn't just any old weed; it was Japanese knotweed, described by the Environment Agency as "indisputably the UK's most aggressive, destructive and invasive plant".

It can grow to 3-4m in just 10 weeks – the equivalent of two grown adults. Underground, its roots – or rhizomes – can spread 7m horizontally and compromise the structure of buildings.

Jonathan Harris, director of mortgage broker Anderson Harris, acknowledges that the problem of securing mortgages on properties affected by the plant has escalated in recent years, despite the fact that it has been around in the UK since the 19th century.

"If a bank's valuer finds evidence of it, or there is a history of it in the area, a specialist survey will be required. Lenders can get quite hysterical and over-react. The bank may not lend, or may retain part of the loan."…

Japanese knotweed shot by H. Zell, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license