Japanese Knotweed Untangled
  • 7th May 2019
  • Article written by Debbie Tree
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You have fallen in love with your dream home but to your horror you or your surveyor has discovered the presence of the dreaded Japanese Knotweed within the boundaries of the property.  You know this is not good but are not to sure of the implications and of course you had your heart set on that particular property.  The good news is in most cases it is not all doom and gloom and whilst alarm bells might be ringing there potentially is a remedy.


Identifying Japanese Knotweed

It is an herbaceous perennial plant which is known to be extremely invasive if not treated properly.  It can be identified by its heart shaped mid-green coloured leaves with a pointed tip and creamy white coloured flowers.  It grows most vigorously in the Spring/summer growing some 10cm per day.


What damage can be caused by Japanese Knotweed

It has been known to cause damage to building structures and substructures by targeting weak points such as cracks in masonry, tarmac and paving.  If left untreated it can cause damage to a property’s foundations as the roots can penetrate deeply into the ground.  Your surveyor would be able to identify the presence of the Knotweed and an inspection by a specialist firm should identify any permanent damage having occurred.  It should be noted that the Knotweed is not harmful to animals but of course once ingested by them this leads to the spread of the weed.


How to treat and remove Japanese Knotweed

Once the presence of Japanese Knotweed has been established and you have decided to continue with your purchase, the owner of the property, if they have not already done so, should immediately instruct a specialist firm to deal with its eradication at their expense.  It is generally recommended that the Knotweed is sprayed with non-residual herbicides over a programme of visits.  During the winter months it should be cut down, dug out, shredded and incinerated whilst the spraying programme continues.  The specialist firm employed to deal with its eradication should issue a Treatment Certificate in line with the Wildlife & Countryside Act 1981 and Environmental Protection (Duty of Care) Regulation 1991.  Once satisfied that the Knotweed has been removed by the end of the programme an Insurance Backed Guarantee should be issued.


What impact can Japanese Knotweed have on your mortgage lender

As solicitors we have a duty to disclose the presence of Japanese Knotweed to your Lender.  Lenders are of course cautious and may withdraw their offer of mortgage however it has been seen recently that so long as proof that a programme of eradication is being carried out with the issue of the appropriate certification of treatment and that the specialist company will provide an insurance backed guarantee the majority of Lenders do confirm that they are happy to proceed.   As solicitors we would recommend that it would be prudent to instruct your surveyor to revisit the property to ensure that all measures are being undertaken and that there is no lasting adverse affect on the property from the Knotweed.


The big question ……Do you proceed?

If you have any doubts or are still at all unsure then you must seek specialist advice, consider the affect it may have on the value of the property and if appropriate renegotiate the price, additionally consider the implications on any future resale of the property.  If you have any other query relating to this article or any other residential conveyancing aspect please do not hesitate to contact us and we would be happy to help.