The Environment Agency has described Japanese Knotweed as “indisputably the UK’s most aggressive, destructive and invasive plant”. Discovery of the weed can wreak havoc on the ability of an owner to sell their home and mortgage providers will often refuse to lend on property located within seven metres of an infestation of the plant.
The ability to penetrate concrete
Introduced from Japan in the 19th century, Japanese Knotweed is a ferocious survivor. Its root system is extensive and robust, and it is almost impossible to control its spread. The plant dies back to ground level in the winter, but when the warm weather comes, its growth rockets – by up to 20cm per day, reaching a height of two meters in some cases. As well as growing like wildfire, Japanese Knotweed’s strong roots, which can penetrate more than four meters deep, can grow through tarmac, bricks and concrete, damaging the foundations of a home or building.
If you discover Japanese Knotweed on your property, there are several options available to remove it.
Cutting it back
Trying to cut back Japanese Knotweed or pull it out at the root is usually futile due to the tangled breadth of the plant’s root structure. The only way to eradicate it by this method is to dig out the entire area down to the base of the root structure. But as with other perennial weeds, every piece of stem that remains in the soil can become a new, invasive plant. Even if you do manage to dig out the plant and its roots, disposal can be difficult since Japanese Knotweed is classed as ‘controlled waste’ under the Environmental Protection Act 1990 and must therefore be taken to a licensed landfill site by a certified waste carrier.
Chemical warfare
Homeowners can use a chemical treatment to eradicate Japanese Knotweed. The solution, a glyphosate-based weed-killer, can be bought over the counter.
Call in the professionals
Eradicating the plant properly can save the value of your home. Although it may cost more, in the long-run, it is far better to engage a professional to remove Japanese Knotweed if you discover it on your property – it is likely to prove the most effective method of removal and can protect you against a civil action should it spread to any neighbouring properties.
The importance of a survey
It is always advisable that you obtain a surveyor’s report on a property prior to exchange of contracts. An experienced local surveyor should be able to identify any Japanese Knotweed which is present at the property, but it is unlikely any Japanese Knotweed within the locality other than at the property will be identified.
Discovering Japanese Knotweed on a neighbouring property
If your neighbour has Japanese Knotweed on their property and it spreads to your land, causing damage, you may be able to bring a civil claim in nuisance. If the claim is successful, your neighbour may be ordered to implement an eradication programme and pay compensation for the harm done to your property.
In April 2017, the case of Williams and Waistell v Network Rail Infrastructure Limited (2017) (County Court) attracted attention because it introduced the possibility that a claim of nuisance may be actionable even if no damage has occurred to the claimant’s property. In Williams & Waistell, the owners of two bungalows brought separate claims against Network Rail, alleging that the presence of Japanese Knotweed on the defendant’s property had lowered the value of their homes as mainstream lenders would not issue mortgages to anyone wishing to buy their land. The judge held that there can be an actionable nuisance if Japanese Knotweed interferes with the value of a property since the owner is not able sell it for its full market value. The claimants were awarded damages for diminution in value of their properties, in addition to an award of damages to fund treatment works and an annual award for loss of amenity.
The decision in Williams & Waistell makes it even more important to ensure that you obtain a survey as part of the due diligence process when purchasing a property.
If you have the plant growing on your property, it is highly advisable that you organise a treatment plan and keep clear records of the actions you have taken to remedy the problem to offer you protection in the event a neighbour looks to bring a civil action against you.
In the event your property has been affected by Japanese Knotweed or you are the subject of a nuisance claim please call our litigation department on 01872 241414.