Japanese knotweed and mortgage advice

Chances are that, unless you have lived under a rock for the last five years, you are already aware of the invasive weed called Japanese knotweed that is yearly widely spreading into various habitats, both wildlife areas such as river banks as well as roadsides, private gardens, temporary vacant commercial properties and residential estates throughout Britain.

Who is this Japanese knotweed guide for?

This article aims to deliver professional hands-on advice on mortgage application related issues causes by Japanese knotweed infestations.

Regularly, we are enquired by home sellers and buyers from across the country, who feel very confused (and scared) when they have discovered a potential knotweed infestation in their garden. Mortgage lenders are not helping in this case, spreading around over-estimated costs of professional Japanese knotweed surveys and management plans that are required before a home sale can be cleared.

TLDR: what should I do?

Provided that you realise the consequences of improper and hasty knotweed dig up (not to mention that knotweed is considered controlled waste and hereby should be utilised at a dedicated facility), the infestation can be, over the course of couple of seasons, permanently eradicated. Your mortgage application, however, should be put off hold as soon as your mortgage company sees a clear proof of a long-term knotweed treatment plan being put in place.

Destructive plant that’s becoming a massive deal for home buyers and sellers

Due to budget constraints, town councils, companies from the private and public sectors are reluctant to have knotweed surveys carried out on their properties ahead of time, before the plants profusely spread onto neighbouring residential properties.

On the other hand, wide media coverage of mortgage application problems attributed to Japanese knotweed infestations is causing a rapid increase of the thoroughness in which mortgage lenders make assessments before any mortgage application is approved.

Increased awareness of knotweed issues amongst mortgage companies has resulted in creating specific guidelines for the financial sector – these severe restrictions are yearly putting thousands of home owners under huge stress during the process of re-mortgaging or house sales.

Even if the invasive weed is discovered growing as far as 7 m from your property boundaries, it still can be considered to pose a potential risk to the structure of the building and the pavement surface, whether it is an asphalt, concrete or tarmac layer.

Profusely spreading, knotweed has the ability to exploit the already existing cracks in concrete building construction and tarmacadam sidewalk surfaces. Over time, worn out tarmac surfaces give in to the plant’s rhizomes forcefully tearing their way through.

It is estimated that knotweed related problems could be costing British economy as much as 1.6 mln GBP each year. (Defra)

This staggering number suggests that for each house sale or purchase, it should be prerequisite of estate agents, home owners or potential buyers to conduct a thorough site survey within the property’s boundaries, especially if other knotweed infestations have been recorded in the area at least 5 years back.

Why it is so important to act quickly?

We can talk about several aspects you can ironically benefit from after a knotweed infestation has been identified in your garden:

  • Obviously, the earlier a knotweed management plan is put in place, the earlier the core treatment can begin and the sooner the plant will be weakened and further growth is ceased.
  • Early discovery of knotweed infestations mitigates the risks of insurance claims (submitted by owners of neighbouring properties) later on. It is not illegal to have Japanese knotweed within your property’s boundaries. However, letting the weed spread onto neighbouring lands is a criminal offence and can result in a court case if you and your neighbour cannot work out a solution to the knotweed problem.

Can I get a mortgage with Japanese knotweed growing on my property?

Any major mortgage company in Britain will be reluctant to grant a mortgage agreement at the presence of Japanese knotweed, however if you conduct a research around local lenders, you may be able to have your application approved.

This will, however, depend on the distance between the infestation and your home – even if knotweed is growing directly in your backyard. It’s commonly considered that knotweed growing 7 metres or further away from the building should not cause your application to be rejected.

Other resources

  1. Find out more about knotweed-related issues with re-mortgaging in this transcription of an interview with one of our specialist Japanese knotweed surveyors: https://theknotweedexperts.co.uk/news-article/tom-goodman-interviewed-by-the-bbc/
  2. Knotweed Code of Practice documentation provided by The Environment Agency in regard to managing knotweed related issues for both sides of the table: mortgage applicants, UK’s mortgage lending companies and banks, provides a detailed guidance for successful knotweed management: https://www.gov.uk/government/organisations/environment-agency
  3. For both Japanese knotweed management practitioners and property owners that are struggling with knotweed infestations on their land, Property Care Association (PCA) has prepared a specialist and concise Code of Practice that outlines adequate methods of knotweed inspections and guidelines for successful methods of eradication. Follow the link to read the document:  Code of Practice for the Management of Japanese knotweed, version 2.7


The Knotweed Experts is a national Japanese knotweed removal contractor offering comprehensive solutions for complete and permanent knotweed eradication on residential properties anywhere in Britain.

If you are a home owner, estate agent or are looking into purchasing a property that bears the risk of knotweed infestation, contact our knotweed surveyors on 0800 122 3310 for obligation-free advice on mortgage related problems with knotweed.


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