To be or knot to be?……….Japanese Knotweed

Japanese Knotweed hit the headlines in 2014, when a man killed his wife after he believed that the knotweed was invading his home. However, it transpired that the knotweed had not yet affected his home. He was convinced that the knotweed would invade his home and leave his property worthless.

What is knotweed?

Knotweed arrived from Japan in 1825 as an ornamental plant and spreads through modified underground stems called rhizomes. Japanese Knotweed is considered to be invasive which can cause serious damage to buildings and construction sites.

The Environment Agency describes Japanese Knotweed as the most invasive species of plant in Britain.

Landowners are under a statutory duty to be proactive in the control and eradication of knotweed. It is an offence under section 14(2) of the Wildlife and Countryside Act 1981 to “plant or otherwise cause to grow in the wild” any plant listed in Schedule Nine, Part II to the Act, which includes Japanese Knotweed.

Under part 2 of the Environmental Protection Act 1990 all Knotweed material (and soil containing Knotweed) is classed as controlled waste and must be disposed of at a licensed landfill site under codes of practice.


The removal, eradication and disposal of the knotweed may be expensive but, given that the presence of it can impede the sale of your property and/or affect the value, the sensible approach would be to have it removed by licensed contractors and properly disposed of.

The costs of treatment can vary depending upon the severity of the knotweed. Professionals can charge between £1,500 and £3,000 if you have a severe knotweed problem – with treatment involving repeat visits for at least five years. This work should also come with an insurance-backed guarantee that the knotweed will not return and will probably involve the removal of potentially contaminated soil.

Lenders Stance

Previously, high street lenders declined Mortgage applications on properties where Japanese Knotweed was present. Gradually lenders have moved their stance and have started to lend and have adopted a measured approach. Some lenders have indicated that, provided the knotweed was at a distance of 7m or more from the property and an appropriate herbicide programme is in place to deal with this threat quite effectively, then they will proceed.

Many lenders are now quite happy to offer mortgages – as long as there is no existing damage to the property structure and as long as their ongoing requirements are met.

Neighbouring Land

Questions arise when dealing with neighboring properties which have issues with knotweed such as:-

  • Who is responsible for the knotweed?
  • Did it grow in your garden and spread to your neighbour’s property?
  • Or did it originate on the other side of the fence?

It is not an offence for Japanese Knotweed to be present on your neighbour’s land but allowing it to encroach onto your property may constitute a private nuisance under common law. It is therefore very important that both parties agree to deal with the invasion of knotweed.

If you cannot agree an action plan and division of costs, you could end up in the civil courts with a claim for damages.

Most buildings insurance policies do not cover the cost of any treatment or removal of Japanese Knotweed.


In 2013, the Property Information Form (TA6 Form) was changed, to specifically include a question regarding Japanese Knotweed. The Seller is now under a duty to disclose whether knotweed exists at the property.

It is important whether you are buying or selling a property that you familiarise yourself with what Japanese Knotweed looks like and whether it affects the property you are selling or purchasing.

If you are looking to sell or purchase a property with suspected Japanese Knotweed, please do not hesitate to call us today on 01902 904060 for further advice.

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