Japanese Knotweed Slashes £20bn Off UK House Prices

The growing problem of Japanese knotweed around the UK has led to a drop of around £20 billion in house prices because those infected with the highly invasive plant are almost impossible to sell, as few people want to take the risk of buying one.

Japanese knotweed was brought into Britain in the early 1800s as a decorative plant. Well-heeled Victorians lapped it up and prized the import from the Orient for its dainty, heart-shaped leaves and pretty, off-white flowers during the summer season.

Little did they know, however, that this is one of the most voracious and fast-growing species in the plant kingdom — and soon enough they, and the botanical gardens that had been displaying the plant, grew weary of its wild ways and got rid of it. In the many intervening years since, Japanese knotweed has grown out of control in the countryside and caused havoc to properies up and down the country.


Big Property Loss

Now, a new analysis of data of Japanese knotweed removal over the past two decades by specialist eradication firm Environet UK reveals the extent of the problem. The company’s figures show that between 850,000 and 900,000 properties in the UK are affected by Japanese knotweed and have suffered around a 10% drop in value — collectively amounting to around £20 billion in property losses.

The problem with Japanese knotweed is not just that it’s an incredibly fast-growing plant that quickly overwhelms everything else in a garden or other parts of a property, but also that it has an incredibly large and deep root network that can potentially cause even more destruction. As the roots seek out moisture to fuel the plant’s growth, tiny roots can work their way into cracks in walls and expand them as they grow larger, leading to structural damage.

And that’s not all. Japanese knotweed can also interfere with underground piping, such as water and sewage pipes, and if it spreads onto neighbouring property, you could be given an ASBO. Improperly disposing of the plant could also land you in hot water with the authorities, with the possibility of fines and other penalties if it’s not buried in the right way so that it won’t start growing all over again.


‘£22,800 Drop’ per Affected Property

UK house prices average around £228,000, according to the Land Registry’s price index, and the estimated 10% lowering of prices due to Japanese knotweed means affected homeowners are hit with an loss averaging around £22,800.

Environet UK founder and managing director Nic Seal said there didn’t seem to be an end in sight to Japanese knotweed woes in Britain.

“Japanese knotweed is the problem that just keeps growing,” he said. “For most people in the UK, their home is their biggest asset and often the ‘pot of gold’ they are relying on in retirement, but Japanese knotweed is having a serious impact on values by deterring buyers and making homes difficult to sell, even if the knotweed has been successfully treated.”


Japanese Knotweed Treatment

Mortgage providers usually won’t approve an application if there’s Japanese knotweed on the property; they will require that professional Japanese knotweed treatment be carried out first. Many people affected by the weed try to deal with the problem themselves, thinking “it’s just a plant” that they can easily spray with weedkiller or even dig up. All too often, though, this turns out to be a long, laborious and expensive process, as the plant keeps springing back to life.

The only real solution, to protect a property and its value, is to invest a relatively small sum in proper Japanese knotweed treatment, so that the plant is killed off for good. And the leading Japanese knotweed eradication firms will provide an insurance-backed guarantee of up to 10 years.

Then you can sleep soundly once more, without worrying about any growing problems around the house.