call-to-action call-to-action-mobile

Buying Or Selling A Property Affected By Japanese Knotweed?

Mon 23 May 2016

We asked Nic Seal, Environmental Scientist and Managing Director of Environet UK Ltd to provide advice to buyers and sellers alike

Whereas rabbits are pre-programmed to eat grass and to go forth and multiply, Japanese knotweed DNA is hell bent on:

Destruction – it loves to damage human property, growing through asphalt, destroying walls and underground drains

Dominance – it spreads rapidly, being present in nearly every 10 sq km of the UK

Survival – it’s extremely difficult to kill, it laughs at DIY methods, and even shrugs off many so called “professional” attempts

That’s why the Environment Agency describe Japanese knotweed as “indisputably the UK’s most aggressive, destructive and invasive plant”. And yes, it can have a drastic effect on residential property sales so buyers and sellers of knotweed affected property should read on, or watch a short video at

What a buyer ought to know when buying a property with Japanese knotweed

The presence of knotweed on a property does not need to be a deal breaker but you do need to understand and be prepared for what you are taking on.

1) Identify whether knotweed is present on the property or in adjoining property

You need to identify whether the property is affected by Japanese knotweed, and, if it is, the scale of the problem. Don’t be fooled into thinking it’s a small problem if there is only a sprig or two, as it is the mass of underground rhizome system that is important. There is a short video at to help you correctly identify Japanese knotweed.

2) How to identify Japanese knotweed

Mature Japanese knotweed canes can be identified by their distinctive purple speckle and stand as high as three metres tall. This is when they are fully grown by early summer. The plants flower towards the end of summer and this consists of small white flowers, which are loved by insects for their nectar. In autumn, the leaves wither and fall off and the canes die back and go brown. The rhizome is the part of the plant that is submerged under the soil. It has a dark brown bark and under this external layer, it is orange or yellow.

3) Understand the liabilities that you’ll be taking on

You need to understand the liabilities the knotweed presents, because it will be your responsibility as the new owner. Has the knotweed encroached from or onto the land you are looking to acquire? If it has, then the first discussion you have with your new neighbours may not be as friendly as you had hoped. If the knotweed has encroached from land that will become yours then you are at risk of a legal claim in “private nuisance” from your new neighbour.

The knotweed may have caused damage to the building. It may not be immediately obvious, but knotweed can cause damage especially to underground elements such as drains.

4) Will the property provide suitable security for lending purposes?

You could experience difficulties securing a mortgage on the property if it’s affected by Japanese knotweed. Some lenders reject outright any property affected by knotweed. Others take a more pragmatic view and lend where the knotweed is being eradicated by a reputable firm and where appropriate insurance backed guarantees are provided.

5) Does anyone have a duty to disclose the presence of Japanese knotweed to the buyer?

The seller has an obligation to disclose the presence of knotweed during pre-contract enquiries made by your solicitor (TA6 Law Society form). However, at this stage you will have invested plenty of money, time and emotional energy, and to have the bad news dropped on your lap at the 11th hour will be unwelcome news.

The estate agent does have an obligation under consumer protection regulations to advise you of any material facts that would affect your decision to buy. The guidance to these regulations identifies Japanese knotweed as being “material” so assuming the estate agent is acting professionally you should be guarded against this eventuality.

And finally if neither seller nor estate agent disclose the presence of Japanese knotweed there’s a strong chance that your lender’s valuation surveyor will result in a recommendation “NOT TO LEND”.

6) If the property is identified as affected by Japanese knotweed should we pull out of the sale?

There is no simple answer to this, as it depends on numerous factors. What you need to do is understand what you are taking on and satisfy yourself that it’s reflected in the price you are paying.

Don’t fall into the trap of letting the seller “sort out” the knotweed problem. A cheap attempt at eradication with inadequate guarantees is unlikely to work. Insist that the work is carried out by a firm that you trust will do the job properly, otherwise walk away.

If you are buying and knotweed is found, get professional advice. You’ll need a survey and Management Plan report which will highlight all the issues, the costs as well as satisfying your lender.

What a seller ought to know when selling a property with Japanese knotweed

A property infested with Japanese knotweed can make it difficult to sell. Buyers would much prefer to buy a knotweed-free property than have to fork out considerable sums of cash to eradicate this highly invasive species.

This is where you as the seller need to make the most out of the situation, in order to make your property attractive to potential buyers.

1) What should you not do when it comes to selling a property with Japanese knotweed?

Intentional concealment is not a good answer! You need to be aware that the Law Society’s TA6 form now has a specific question relating to Japanese knotweed and if answered untruthfully during the conveyance process, a legal claim of misrepresentation could possibly be brought against you by the buyer.

If you do try and conceal the knotweed, there are now highly trained RICS Surveyors, whose task it is to spot knotweed and bring it to the attention of interested parties, especially the lender.

2) What is the correct way to go about removing Japanese knotweed and improving the chance of selling?

If time is available then commissioning a remediation firm to eradicate the knotweed and provide suitable guarantees will be advantageous. Don’t fall into the trap of DIY attempts. Be aware that inappropriate treatments, through the use of ‘off the shelf’ herbicides, can actually induce rhizome dormancy and make any subsequent treatment more difficult and costly. This may make it impossible to obtain an insurance backed guarantee, which will be required by any buyer requiring a mortgage.

It’s best to engage the services of a reputable knotweed specialist who can eradicate the knotweed and provide suitable insurance backed guarantees which will be acceptable to all lenders. And make sure that the guarantee can be assigned to your prospective purchaser.

3) How to get rid of Japanese knotweed

Getting rid of Japanese knotweed yourself is not easy and takes patience! The most popular technique is to use a glyphosate herbicide but this will require a high dosage and it will not be eradicated after just one dose. It will require repeated doses to completely rid your garden of Japanese knotweed. If you are diligent in ensuring you are not inadvertently spreading it across your lawn, repeated mowing can also deplete the plant until it withers back. It can also be dug out, but only if you are meticulous in ensuring that there are no traces left in the ground. In fact, the best way to rid your garden of Japanese knotweed is to combine all of the above methods.

4) Examples of Japanese knotweed damage to property

Japanese knotweed can cause serious structural damage to property. The rhizomes – the submerged part of the plant – can grow as deep as three metres underground and spread across an area as far as one hundred metres. As well as undermining concreted pathways and patios, it can also grow under foundations and affect the integrity of them.

This information can be found on

"The experience of selling our home was made stress free by the professionalism, helpfulness and kindness of the staff. Communication was key which was forthcoming constantly to the end. I would recommend Anker & Partners to anyone wishing to sell their home "
Sarah Ball - Vendor

News Archive

January 2020

What is a leasehold property and how do I extend a lease?

November 2019

Charity Santa 5km Fun Run

September 2019

A Guide to Shared Ownership

May 2019

9 Top Tips for Selling Your House (AND 3 MISTAKES YOU SHOULD AVOID)

June 2019

How to prepare your garden before selling your home

April 2019

6 Top Tips to Help First Time Buyers Get on The Property Ladder

A Guide to Downsizing (or 'Right-Sizing')

A guide to getting your home ready for viewings

January 2019

How to use Rightmove tools

December 2018

Christmas Opening Hours 2018

November 2018

Help to Buy ISA. Everything you need to know

September 2018

Five tips to help you feel at home in a new property

August 2018

Prioritise your search with Keyword Sort

June 2018

GrangeFest 2018

Why you should check your credit score before searching for a new home

April 2018

Overseas Homes

March 2018

Property viewings: 9 tips for finding 'the one'

Conveyancing: Advice For Homebuyers

February 2018

Seven top tips for today’s first time buyers

December 2017

Happy New Year!

Merry Christmas!

Christmas Opening Hours 2017

Unwrap your perfect home this Christmas

November 2017

Stamp duty scrapped on homes up to £300,000 for first time buyers

Top tips for dealing with the Bank of England’s 0.25% base interest rate rise

February 2018

Top tips for reducing condensation

July 2017

Broughton Castle Sportive 2017

Bodfest 2017

May 2017

The London & Country Property Show 2017 - Update

April 2017

The London & Country Property Show 2017

March 2017

On The Markets guide to house price indices

Plans for a £50 million waterfront leisure development in the heart of Banbury have be unveiled.

February 2017

Is your home in an area prone to flooding? What to do if disaster strikes?

January 2017

House prices: Whats in store for 2017?

December 2016

Merry Christmas and Happy New Year

Christmas Opening Hours

November 2016

Hugh Grants Former Bachelor Pad For Sale

Tories pledge to build 40,000 more affordable homes in Autumn Statement 2016

Winter-Proof Your Home SOS

October 2016

Spamalot - Banbury Operatic Society - Tickets on Sale

Keeping your home damp free

What The Bank Of England Base Rate Cut Means For Mortgage Holders

September 2016

Moving to a new area? Top tips to help ease moving house

August 2016

Buying or selling a property with asbestos?

July 2016

3 Ways RICS Home Surveys Pay For Themselves

June 2016

Buying or renting a listed building? Everything you need to know

10 Secrets To Achieving Show Home Style

May 2016

Buying Or Selling A Property Affected By Japanese Knotweed?

Can Overpaying Your Mortgage Save You Money?

All You Need To Know About The Lifetime ISA

5 Ways To Protect Your Home From Flooding

April 2016

One in four of today’s first-time buyers will be paying off mortgages in retirement

Anker and Partners sponsored football kit being re-used in Sierra Leone!

February 2016

Sky Dive to Raise Funds for the Blue Cross

Is it cheaper to rent or buy a home?

January 2016

Will UK house prices continue to rise in 2016?

Supporting Dogs for Good

UK Stamp Duty - What changes to expect in 2016?