The Perils of Japanese Knotweed

October 2016

Fallopia Japonica (more commonly known as Japanese Knotweed) is an invasive plant, well known for being extremely difficult to eradicate. It grows so vigorously, spreads so rapidly, and its root system is so powerful that in a relatively short time it can cause structural damage to paving, roads, retaining walls and even the foundations and drainage system of a property.

Its potentially devastating effects make a property affected by Japanese Knotweed much more difficult to sell – and risky to buy. In fact the risks are so significant that, if it is identified in or around a property, either by a potential buyer or their surveyor, they may reduce the price they’re prepared to pay for it or withdraw from the transaction altogether.

Not only is Japanese Knotweed difficult and expensive to remove, but, if you’re buying with the help of a mortgage, some lenders may take the view that a property affected by Japanese Knotweed (even if it is in a neighbour’s garden) doesn’t offer good enough security for their loan.

The Council Mortgage Lenders has published a policy page explaining the difficulties with this ornamental plant. Their website explains:

“If left untreated it can cause physical damage to property. However, it can be successfully treated and eradicated - although, depending on how invasively the Knotweed is established, this can be both difficult and expensive, and repeated treatments over years may potentially be necessary.”

In September 2015 the Royal Institution of Chartered Surveyors issued an addendum information paper aimed at informing valuers of residential property on how to survey property affected by Japanese Knotweed, which states:

”As standards develop across the treatment industry, it is likely that lenders will begin to specify that the management plan provider is an ‘appropriately qualified person or company’ such as an accredited member of an industry recognised trade association such as the Property Care Association (www.property-care.org/ invasive-species) and the Invasive Non-Native Specialists Association (www.innsa.org).”

The Property Information Form which is normally completed by a seller in the early stages of a transaction specifically asks if the property being sold is affected by Japanese Knotweed. However, prospective purchasers would be well advised to carry out their own inspection for evidence of Japanese Knotweed, and to instruct a reputable surveyor to investigate if they suspect that it may be present.

If you are considering buying or selling a property, and have any concerns regarding the implications of Japanese Knotweed, please contact our Gloucester Property Department on 01452 508800.