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Japanese Knotweed Cases up by 28% in Five Years in the UK

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Japanese knotweed cases have increased by 28% in the last five years, according to a study by, analysing data from 49 environmental organisations. South Yorkshire has seen the biggest increase of 77.19%, with a total of 1,111 confirmed cases over the past five years. Wales and counties around London have also seen a large increase in cases.

The invasive species has caused headaches for homeowners for decades. The plant is so hard to control and eradicate that it is against the law to allow it to spread beyond your own land.

Japanese knotweed can make a property more difficult to sell and mortgage. It can also affect the value of people’s homes. For example, a YouGov poll revealed that nearly 80% of buyers would be put off by Japanese knotweed.

However, it is legal to sell a home with Japanese knotweed on or near the land. So, buyers need to be careful about what they are getting into if looking to buy a home affected by Japanese knotweed.

Where does Japanese knotweed grow in the UK?

There are very few places where Japanese knotweed hasn’t spread, but it is particularly notorious in the North West of England, the Midlands, Wales and London.

Wherever you are in the country, if you’re buying a home, you should check for the presence or the risk of Japanese knotweed. You should get a survey, and your conveyancing solicitor will make enquiries with the seller to ensure you’re not caught out.

What is the law on Japanese knotweed?

Planting or growing Japanese knotweed

Japanese knotweed is a ‘controlled plant’. It is not illegal to grow on your own land, but you cannot plant it in the wild or let it spread beyond the borders of your land. It can be a criminal offence to cause or allow invasive plants such as Japanese knotweed to grow in the wild.

The courts can also serve Community Protection Notices (formerly Anti-Social Behaviour Orders (ASBOS)) on people whose conduct has ‘a detrimental effect on the quality of life of those in the locality’. This is flexible enough to apply to someone growing Japanese knotweed.

Disposing of Japanese knotweed

Soil can easily be contaminated with rhizome material (a plant’s main underground stem), so there are environmental laws controlling how you dispose of Japanese knotweed.

Japanese knotweed must be disposed of at licensed landfills and buried at least five metres deep.

Selling a home with Japanese knotweed

When someone sells their home, they need to fill in a Property Information Form (also referred to as a TA6 form) to provide the buyer with information about the property.

The TA6 form informs the seller that, “the plant consists of visible above ground growth and an invisible rhizome (root) below ground in the soil. It can take several years to control and manage through a management and treatment plan, and rhizomes may remain alive below the soil even after treatment”.

In consideration of this, the seller should state whether the property is affected by Japanese knotweed and (if yes) whether there is any Japanese knotweed management and treatment plan in place, which should be supplied with any insurance policy linked to the plan.

Only if the seller is certain that no rhizome material is present in the soil or within three metres of the property boundary should they answer ‘no’.

If a seller lies or is wrong about Japanese knotweed on their property, the buyer may be able to bring a legal claim against them for compensation.

Buying a house that might be affected by Japanese knotweed

Japanese knotweed can do more than cause an eyesore in your garden. It can work its way into the structure of your home, causing serious damage. It spreads like wildfire and can dominate other plant life in your garden. It is also extremely difficult to get rid of and can take several years to manage and eradicate.

For these reasons, buyers and mortgage lenders are understandably reluctant to invest in a property affected by Japanese knotweed. The plant can reduce the value of a property and make it hard to sell and mortgage.

To ensure a property you are interested in buying isn’t affected by Japanese knotweed, make sure you conduct an independent survey and ask the surveyor to check for the plant.

Your conveyancing solicitor will also ask the seller to complete a Property Information Form or a TA6, which has a specific question about Japanese knotweed.

Sellers and their estate agents are legally required to be honest about the property, so they cannot lie and say it isn’t affected by Japanese knotweed if it actually is.

On the TA6, the seller must reply ‘yes’, ‘no’, or ‘not known’ as to whether the property is affected.

‘Yes’, there is Japanese knotweed

If the seller responds ‘yes’, you need to have a serious think about whether going ahead with the purchase is right for you. Most buyers decide it’s not worth the trouble. If you do decide to proceed, your solicitor will review any Knotweed Management Plan and provide advice.

‘Not known’ whether there is Japanese knotweed

If the seller says answers the TA6 Japanese knotweed question with ‘not known’, your conveyancing solicitor should go back with further enquiries. A Japanese knotweed survey can also give you a clearer picture of the state of the property.

‘No’, there is no Japanese knotweed

Most sellers respond with ‘no’. In most cases, this is true. However, if it turns out to be untrue and the property is affected, you may have grounds to bring a legal claim against the seller for compensation.

Get expert advice about buying a home

At Bird & Co, we are a specialist firm of Law Society accredited conveyancing solicitors who help people across the UK buy and sell their homes.

We can handle all the legal aspects of your transaction on your behalf, including conducting enquiries and making sure you have all the information about the property that you need to confidently proceed with your purchase.

Get a conveyancing quote online to see how much your transaction is likely to cost, then a member of our conveyancing team will be in touch shortly.