Japanese Knotweed – be afraid, be very afraid (if you are a homeowner)

 

We tend to think of threats to our property such as beetle infestation, rising damp or flooding. However, it is becoming clear that one of the most potent threats is an innocuous-looking plant called Japanese Knotweed.

Japanese knotweed is an aggressive and invasive species of plant that costs landowners, local authorities, and building developers thousands of pounds each year in removal fees and project delays.

Since its introduction to the UK in the 19th century from the Far East due to the beauty of its flowers, Japanese knotweed has had a negative impact on the UK’s ecosystems, causing damage to buildings, walls, hard standing, drainage systems, and flood defences. The risk of structural damage caused by Japanese knotweed to property has led mortgage lenders to refuse to lend on properties affected, which in turn can see properties down valued. Unless the infestation is eliminated, prices of properties can be adversely affected.

When buying a property, it is always advisable to instruct an RICS qualified surveyor to undertake a Homebuyer’s Report or the more comprehensive full structural survey, in order to have a clear picture of the state of the property. Surveyors are trained to spot plant infestations and Japanese knotweed in particular. It is also worth knowing that it is a criminal offence for sellers not to reveal Japanese knotweed infestations, which emphasises the level of importance that the authorities place on trying to identify and eradicate this menace.

A study by scientists found the plant is impossible to manage with standard measures and homeowners are unable to control the spread of the plant themselves. Its destructive ability means it can be a nightmare for homeowners, as it not only poses a structural risk but its very presence can reduce a property’s value by as much as ten percent. For anyone wishing to eradicate the infestation, only recognised Japanese knotweed eradication companies are qualified to eradicate it once it takes root. Costs can start from £5000.

It is estimated it would now cost £1.5 billion to clear the UK of knotweed.