Bolton revealed as hotspot for 'aggressive' Japanese knotweed

The hard-wearing vegetation is infamously difficult to kill and can knock as much as 10 percent from the price of a home if you are trying to sell.

It grows at an incredible rate - sometimes as quickly as 10cm a day - and can go unnoticed during the winter months as it dies back to ground level.

Data from removal firm Environet places Bolton as the North West’s most infested area, with more than 650 sightings of Japanese knotweed within 4km of the town centre since the start of the year.

Nic Seal, founder and managing director of the company, explained that these outbreaks can cause major issues for property owners who are legally obliged to warn about knotweed before they sell a building.

“Japanese knotweed has become a major problem in the North West, particularly in towns and cities with a strong industrial heritage such as Bolton, Blackburn and Liverpool,” he said.

“It is impacting property prices, halting sales and causing a huge amount of stress and worry for homeowners.”

As well as causing problems for buyers, the non-native species can create problems for people looking for mortgages, with banks often unable to agree a loan until a comprehensive treatment plan is created.

In addition, sellers are required by law to inform potential purchasers whether their home is, or has been, affected by Japanese knotweed, which Mr Seal says can act as a deterrent even if the infestation has been treated.

He added: “At times such as this when the property market is slow and fewer homes are being bought and sold, it continues to spread unchecked.

“Anyone thinking about buying a property in the region, particularly in these hotspots, would be wise to check the number of infestations in the proximity of their postcode and consider instructing a Japanese knotweed survey on the property.”

The problem is that the owners of homes are liable for removing these aggressive plants, a process which can be expensive and extremely time consuming.

Cllr Adele Warren, Bolton Council’s executive cabinet member for environmental service delivery explained that, while it is not illegal to have the plant growing around your home, it is your responsibility to stop it spreading into wild areas.

She said: “You can have a nuisance order placed against you if it spreads to other areas and because it spreads so fast that is a possibility.

“Because of how fast it grows it can also cause damage to properties.”

Public organisations can also be liable for the spread of the weed, Bolton Council is responsible for stopping infestations which are spotted within five metres of anyone’s property.

A spokesman for the council said: “We treat to control Japanese Knotweed on council land if it is growing close to the property boundary, in an ornamental area or in an area that is due to be mowed.

“We also treat the growth if it threatens sensitive wildlife habitats.

“Residents with Japanese Knotweed on their land should follow Environment Agency advice to stop the plant from spreading.”

The weed can grow particularly quickly across waterways where sections of the plant fall into the water and are carried downstream to start new infestations in other areas.

While the plant is thought of as a nuisance in the modern day, it was its status as a designer garden feature during the 19th Century which initially accelerated its growth Mr Seal explained.

He said: “If you look historically, about how the stuff his spread, in the early days, around 1850-1870, it was planted in some of the biggest estates around because it was a plant that was prized by horticulturalists.

“It was not until later, around 1880, that people realised that it was not that great because it is very difficult to get rid of.

“The other reason that we see so much of it is that it is spread accidentally by people in moving soil around but not understanding what they are dealing with.

“We see an awful lot of sites where someone’s had an appalling attempt at getting rid of knotweed.

“Plus, every time you cut it back you take the risk of it propagating in the ground.”

Anyone interested in finding out about infestations of Japanese knotweed near their homes can get more information through Environet’s ‘Knotweed Heatmap’.

The interactive tool shows parts of the UK which have become particular hotspots and allows people to report infestations they have seen either on residential or public land.

For more information, to take a look at the map or to make a report about a sighting, visit:

environetuk.com/exposed-japanese-knotweed-heat-map

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