Mortgage lending and Japanese Knotweed

japanese knotweed and mortgaging

Watch out for Japanese Knotweed

One of our major lenders has today issued a new warning and details of lending policy realting to Japanese Knotweed. The policy of all lenders will be similar in relation to this plant and both buyers and homeowners should take care if Japanese Knotweed is seen anywhere near their existing or intended property.

A typical lenders’ approach to this problem would be:

Presence of Knotweed within 7 metres of the building – the property will be assessed as an unsuitable security for lending. A report will be requested with regard to eradicating the plant and repairing any damage already caused.

Following receipt of the specialist reports the property will be reassessed to establish if the property can be considered suitable security and whether a retention of funds is appropriate.

Presence of Knotweed beyond 7 metres of the building – The lender will require the applicant to confirm they are aware of the presence of Japanese Knotweed and having considered this, that they still wish to proceed with the purchase.

Why is Japanese Knotweed of concern to lenders?

The aggressive nature of the plant’s growth and the strong and vast root system causes dramatic damage to buildings and building services. The precence of the plant therefore puts the lender’s security at risk.


Japanese Knotwood anywhere near a property can lead to removal costs today or potentially dramatic repair costs later – a severe investation will render the property unmortgageable.

What is Japanese Knotweed?

Japanese Knotweed (Fallopia Joponica) is a large, herbaceous perennial plant, which is native to eastern Asia, particularly Japan, China and Korea.

The species is now growing very successfully in the North America and Europe and is classified as one of the worlds 100 worst invasive species.

You may also hear Japanese Knotweed referred to as:

  • fleeceflower
  • monkeyweed
  • monkey fungus
  • elephant ears
  • Japanese bamboo (it is not bamboo)
  • donkey rhubarb

A plant that likes roadsides and waste sites, Japanese Knotweed crowds out other herbaceous species and is resilient to cutting as it re-sprouts roots vigorously.

The most effective method of control has proven to be herbicide although a trial using sea water has also proved effective.

On development land the large network of roots can be evacuated but this causes an additional problem as the roots as classified as controlled waste in the UK and therefore disposal is subject to regulation.

So, what use is Japanese Knotweed?

The plant can be used as a vegetable with the stems edible when young,  it is widely favoured by beekeepers as a source of nectar producing a flavoursome honey.

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