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How Japanese knotweed could affect house values

Without correct treatment from glyphosate-based herbicides, invasive weeds can cause incredibly damaging, and costly, problems

Japanese knotweed is highly invasive; it spreads fast, and grows high above ground and deep below it, blocking sunlight and damaging concrete foundations and brick walls.

When the plant began growing on a railway track embankment in Wales, spreading on to nearby domestic properties, two homeowners decided to take action.

In a David versus Goliath scenario, neighbours Robin Waistell and Stephen Williams of Maesteg took the UK’s largest rail company, Network Rail, to court. They won compensation for a drop in the value in their property caused by the knotweed infestation, which happened because of Network Rail’s failure to treat the knotweed with weedkiller. Network Rail has since launched an appeal against the decision.

The court recorder ordered that the knotweed, which had been left untreated for four years on Network Rail’s land, had caused loss of enjoyment of the property for Waistell and Williams, and awarded damages of £10,500 towards diminution of their property value and £5,000 towards the cost of removing the knotweed.

Williams said: “I know it’s a victory but it doesn’t feel like it. The knotweed is still growing at the back of my house and you can follow it down the track for five miles. The judge has ordered Network Rail to treat it but until that happens I can’t sell my house, it’s still devalued.”

“The judge has ordered Network Rail to treat the knotweed, but until that happens I can’t sell my house.”
Stephen Williams, homeowner from Maesteg, Wales

The scale of the problem

For the rail company, which operates 20,000 miles of track across England, Scotland and Wales, the court order could set a precedent for millions of pounds worth of damages to thousands of homeowners inconvenienced if the company fails to control the spread of weeds from trackside to neighbouring properties.

Network Rail barrister Andy Creer said: “Network Rail has thousands of miles of track across the country and any number of people whose land adjoins those tracks. This will have a significant impact on our company fulfilling its primary duty to ensure the safe operating of the rail network.”

Williams’s lawyer, Samantha Towle of JMP Solicitors, said: “Every homeowner should be able to sell their home at its proper value, but UK mortgage companies do not like to lend on properties that have knotweed within seven metres of a property boundary. So, through no fault of his own, our client found the value of his house significantly affected by knotweed growing close to the boundary.”

An expert opinion

Like JMP Solicitors, Waistell’s law firm, Charles Lyndon, is a specialist knotweed litigator, and it called on environmental consultancy Phlorum to provide expert witness services in the South Wales case.

Paul Beckett, co-founder of Phlorum and a specialist in the treatment of Japanese knotweed, said: “We identified an awful lot of knotweed right along the track. And it had been there for a very long time.

“In this case, glyphosate-based weedkiller, has been sprayed too late in the season and too little has been applied. As a result, the homeowners had a veritable knotweed forest blocking their windows in the summer.”

He added: “As for talk about an EU ban on glyphosate, that would increase the problem. Glyphosate-based weedkillers are a safe, affordable and effective knotweed killer. The alternative is full excavation, which is very expensive.”


Why glyphosate is vital

Another specialist, Tom Payne, managing director of TP Knotweed Solutions, reiterated the weed control industry’s hope for the renewed EU approval of glyphosate.

Payne said: “If the case against Network Rail is ultimately successful, it will face a big problem as it has Japanese knotweed infestations along many of its tracks, especially around London.

“We provide excavation services for our property developer clients, and glyphosate is our preferred herbicide to treat such weed infestations.”

Without effective herbicides, Network Rail and many other landowners could face ever-increasing damages claims when the weeds on their land encroach upon, and damage, the properties of their neighbours.