Japan Knotweeds and Mortgages

I will excuse my reader for being a bit surprised and flummoxed when reading that this mortgage adviser is now writing a post about a weed!

“Surely that’s not relevant to me”, I hear you say. After all you are 35, on £75,000 a year with no debts, and a 999-credit score. What could possibly go wrong now?

Well hopefully and most likely nothing.

However, I have noticed recently an increase in questions to me about Japanese Knotweed.


Well, let’s get horticultural and let’s look at a very different problem.

Japanese Knotweed is an invasive species of plant, originally introduced as an ornamental variety.

If left untreated it can cause physical damage to property. However, it can be successfully treated and eradicated – although, depending on how invasively the knotweed is established, this can be both difficult and expensive, and can require repeated treatments over a number of years.

If you’re after an indication of how serious the issue can be, visit the Government’s website to learn more.


Lenders determine their individual policies on this issue.

If Japanese Knotweed is present, it is usually one of a number of factors the lender will consider, and the level of severity may be a factor. In the worst cases, it could mean that they’ll decide not to lend on that particular property.

If mortgage lenders agree to lend on an affected property, they will normally require evidence of treatment that will eradicate the plant as a condition of lending.

Once again, I have included the view of 2 lenders on the dreaded Japanese Knotweed.


Properties with Japanese Knotweed growing within the vicinity are considered with caution and subject to the following terms:

  • If present within 7 metres of the property boundary, the applicant will be required to obtain a specialist report in respect of eradicating the plant, including an insurance backed 5-year warranty against re-appearance of the plant, and if necessary, repairs to the property and services will be required for the valuer to make a full assessment of the property’s suitability.
  • If more than 7 metres from the property boundary, written confirmation is required from the applicant confirming that they are aware of the presence of this invasive plant and the adverse effects it could have on the property should it spread closer. It is recommended the applicant seeks their own independent professional advice regarding the risk this plant might impose


Properties affected by Japanese knotweed, RICS categories 1 and 2, are acceptable subject to a satisfactory valuation report.

Category 1 – Japanese knotweed was not seen on the property, but it could be seen on a neighbouring property or land where it was more than seven metres away from the boundary.

Category 2 – Japanese knotweed was not seen on this property, but it was seen on a neighbouring property or land within seven metres of the boundary but more than seven metres away from habitable spaces, a conservatory and/or a garage.

Properties affected by Japanese knotweed that do not meet the above criteria are unacceptable.


It is not a straight “no”, but it is a guarded maybe!

The message is clear; please look at all aspects of a property when you are looking to buy. Even the garden!

Lenders are prepared to be more helpful than perhaps they used to be, but they will want the odds in their favour.


For any help or advice with anything related to the world of mortgages, please contact Mark on 01453 887179 or via email at: mark@hhhmortgages.com.