Property values dropping because of Japanese knotweed

Japanese knotweed is an invasive plant that is known for the damage it can cause to homes, businesses and gardens. It’s bamboo style stem and roots will destroy all other plants in its surroundings by depriving them of their key nutrients. The roots can also cause damage to buildings and their foundations, but how true is this?

A report published last week suggests the risk of damage from Japanese knotweed is being overplayed and exaggerated by mortgage lenders. This ‘over-cautious’ approach can leave homeowners with low property value, or even unable to sell their home.

The plant was first introduced to the UK in the mid-nineteenth century as an ornamental plant in parks and gardens but has since become a problem that cost Britain an estimated £200 million in 2018 alone.

The plant’s roots are so strong they can grow through the pavement, cracks in buildings and damage the foundations of houses. It’s can also be extremely difficult to eradicate, often needing treatment or excavation.

Despite the damaging effect this plant may have, recent research suggests that it “might not be as significant as previously believed.” Highlighting that there are other invasive plants that don’t have the same effect on house prices as Japanese knotweed.

The report states that arguably Japanese knotweed is no more dangerous than any other disruptive plant or trees.  A report published by the science and technology committee has found that banks might be adopting an overly cautious approach to this plant. Where it may be right to include information on Japanese knotweed on the seller’s property information form, it should not have a significant effect on mortgage lenders decisions.

The report proposes there should be an evidence-based approach when dealing with this issue. The so-called ‘seven-metre rule’ is often used by mortgage lenders.  It is within this distance that the plant is considered to pose a significant risk of damage to buildings, however, it is now thought this lacks a solid evidence base.

Do you have a question or a project you need help with? Contact us.