Japanese knotweed (Fallopia japonica) has made headlines over the years as a mysterious plant capable of growing through concrete, ruining back gardens, and even making it difficult to get a mortgage. But what exactly is it, and why does it pose such a problem for homebuyers?

What is Japanese knotweed?

Japanese knotweed looks a lot like bamboo, featuring long stems, small white flowers, and leaves positioned in a zig-zag pattern near the base. For many years, it was grown as an ornamental flower much like bamboo, but when introduced to Europe it began to grow as an aggressive weed.

Because it originates in Japan where the soil is volcanic and dry, Japanese knotweed flourishes in European soil, no matter how poor.

Why is it a problem?

Japanese knotweed is so strong that it’s been known to grow through pipes, brickwork, roads, and concrete. This means it’s capable of causing damage to buildings, driveways, and gardens – all of which contribute to the overall value of a property.

If the property has Japanese knotweed will I be able to get a mortgage?

As a rule, mortgage lenders in the UK don’t offer funds to buyers looking to secure a mortgage on a property with Japanese knotweed. There is, however, an exception to this rule – if there is a Knotweed Management Plan put in place by a professional eradication firm, the lender may release funds for the mortgage.

There are guidelines regarding how much value a property loses if it is found to have a Japanese knotweed infestation within 7 metres of its boundary.

Usually, a discovery of Japanese knotweed on the land of a property would mean that a buyer would not be able to secure a mortgage. This applies if the plant is found on neighbouring land, too, as it poses a risk of spreading across property boundaries.

How can I get rid of Japanese knotweed?

Getting rid of Japanese knotweed is expensive, time-consuming, and difficult. In most cases, the only way to completely eradicate the weed is through expensive systemic herbicide treatment. This can take many years and does not always prove completely effective.

For advice regarding the sale or purchase of a property featuring Japanese knotweed, get in touch with a member of the Sweeney Miller team today.


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