Science

Could YOU spot Japanese Knotweed taking root in your garden?

Would you know how to spot Japanese Knotweed taking root in your garden? The invasive plant looks very different taking root in the spring than in the autumn.

There are over 50,000 known Japanese Knotweed infestations throughout the UK and plant is notorious for its ability to spread and cause damage to building structures. 

The plant can be difficult to remove without professional help.

The Japanese knotweed changes its look with the seasons, therefore it is essential to note that when you are checking for Japanese knotweed, you should bear in mind the time of year.

It is incredibly durable and fast-growing, and can seriously damage buildings and construction sites if left unchecked.

There are over 50,000 known Japanese Knotweed infestations throughout the UK and plant is notorious for its ability to spread and cause damage to building structures

There are over 50,000 known Japanese Knotweed infestations throughout the UK and plant is notorious for its ability to spread and cause damage to building structures

Identification 

It is important to know how to identify knotweed. 

The appearance of Japanese knotweed changes with the seasons, so it is important to note that when you are checking for, you should bear in mind the time of year. 

It is most easily identified during the spring months. Red shoots emerge in spring, small cream-coloured flowers blossom at the end of summer, the leaves are shield or shovel-shaped and the stems look like bamboo canes. 

During the summer, Knotweed forms dense clumps of foliage with the green leaves, which are accompanied by a number of small yellow flowers

In the autumn, the leaves will start to go yellow and wilt as winter approaches. The plant can grow to about two or three metres if left unattended. 

The stems will change to a darker brown before the plant becomes dormant in winter.

It is most easily identified during the spring and summer months. Red shoots emerge in spring (pictured)

It is most easily identified during the spring and summer months. Red shoots emerge in spring (pictured)

During summer, Knotweed forms dense clumps of foliage with the green leaves accompanied by a number of small yellow flowers (pictured)

During summer, Knotweed forms dense clumps of foliage with the green leaves accompanied by a number of small yellow flowers (pictured)

In the beginning of autumn, the dense thickets of leaves will remain, but they will begin to turn yellow in colour

In the beginning of autumn, the dense thickets of leaves will remain, but they will begin to turn yellow in colour

Throughout the colder months the stems (pictured) will change to a darker brown before the plant becomes dormant in winter

Throughout the colder months the stems (pictured) will change to a darker brown before the plant becomes dormant in winter

Background: 

The fast-growing weed was brought to Britain by the Victorians as an ornamental garden plant and to line railway tracks to stabilise the soil. 

It has since spread across the country, with many impacted areas seeing incessant return of the plant.

It is controlled by fungus and insects in Asia but in the UK there are no natural enemies, meaning it can wreak havoc on British gardens.

In the US it is scheduled as an invasive weed in 12 states, and can be found in a further 29.

The notorious plant strangles other plants and can kill entire gardens. 

Capable of growing eight inches in one day it deprives other plants of their key nutrients and water.

Last week, a court determined that accountant Jeremy Henderson failed to mention the presence of knotweed before selling his old house

He now faces a potential court bill worth £200,000.

A furniture designer who bought his £700,000 dream home only to find Japanese knotweed lurking behind the garden shed (pictured) has successfully sued the seller

A furniture designer who bought his £700,000 dream home only to find Japanese knotweed lurking behind the garden shed (pictured) has successfully sued the seller

Jonathan Downing, 30

Jeremy Henderson, 41

Jonathan Downing (left), 30, bought his three-bedroom house in affluent Prince George’s Avenue, Raynes Park, south-west London, from chartered accountant Jeremy Henderson (right), 41, in August 2018

Despite the insidious nature of the plant, it is possible to take steps to avoid it from invading your home, according to two Japanese Knotweed experts Evironet UK and Phlorum.

Follow MailOnline’s guide below…

Top tips for protecting your property

Like it or not, knotweed can put any property at risk across the country. See the map to find out if you live in an area at risk of the invasive plant. 

Simply enter your postcode to check for the number of verified infestations within a 4km radius. The worst affected locations are highlighted in red, orange and so on. 

 

Check out surrounding areas 

Don’t just focus on your property. Look over the fence into neighbouring properties to see if knotweed might be located there that could affect your property in the future as it grows to cover a larger area.

Talk to your neighbours to find out local knowledge on the potential history of knotweed in the area. Has it been present on others’ property and was it treated a long time ago? If there is shared liability, how can you work with your neighbours to effectively treat the problem and potentially share costs? 

If your neighbour fails to deal with it, consider installing a specialist root barrier to prevent it spreading onto your land. If it does spread onto your land, your neighbour could be liable. 

Fly-tipping is common source of knotweed spreading to new areas, so if you see any signs of this be particularly vigilant in looking for knotweed amongst the waste.

Get professional help

Don’t try and dig Japanese knotweed out yourself. Movement of the ground is likely to stimulate growth and if a piece of rhizome the size of a fingernail is left behind, it can regrow. Bear in mind the roots can grow more than 2 metres deep and several metres laterally, so what you see above ground is only a small part of the problem.

Other methods such as burning it and burying it are also unlikely to be successful. It’s a job best left to the experts.

Selling your home

Get a professional survey done. An appropriate report from an RICS surveyor should look for obvious signs of knotweed and provide appropriate advice accordingly. The advice might be to get a knotweed specialist in. 

RICS surveyors will usually focus on potential building defects, so they might not be particular confident in identifying knotweed (particularly if it has been partially treated, disturbed or even hidden).

If you get a professional survey done, you might be protected from legal action if the buyers later find knotweed on the property and they try to blame you for it.

An appropriate report from an RICS surveyor should look for obvious signs of knotweed before you sell your property

An appropriate report from an RICS surveyor should look for obvious signs of knotweed before you sell your property

Take photographs of the outside areas of your property so that you have a record of what is there in case a buyer tries to blame you for knotweed that might appear there in the future. It’s important to do this in the growing season (early spring), as knotweed might not show up as obvious in winter photographs when the stems die back.

If you find knotweed on your property it is important that you get it treated professionally.

Insist on an IBG (insurance-backed guarantee) for the work, which protects the homeowner and lender even if the knotweed company ceases trading. Ten-year guarantees are best. 

If you try to hide the problem or treat it yourself without a guarantee, you are potentially opening yourself to expensive legal action. 

Buying a property affected by knotweed 

If you’re buying a property with knotweed, insist on seeing copies of the professional Japanese Knotweed Management Plan and the insurance-backed guarantee. Ensure the work is carried out by a firm you trust, whose guarantee will be accepted by your mortgage lender.

Make sure you understand exactly what you’re taking on. Bear in mind you will also need to declare that knotweed has been present when you come to sell in the future, which could impact the price you achieve even if the knotweed has gone.

Be aware that you will need to declare that knotweed has been present when you come to sell the property in the future

Be aware that you will need to declare that knotweed has been present when you come to sell the property in the future

Think about potential damage. If knotweed is growing close to the property, it could have damaged underground elements such as drains, even if you can’t see it above ground. A JustCheck™ survey will recommend if further investigation is required.

If you’re buying a new home, ask your solicitor to make direct enquiries to the developer about whether the land was affected by knotweed. Developers aren’t always obliged to complete a TA6 form, so unless your solicitor asks directly, you may be none the wiser.

How dogs are used to detect knotweed

Sniffer dogs are known for detecting all sorts from illegal substances, explosives to blood. 

But did you know some pups can sniff out Japanese knotweed infestations? And can save a property seller from being sued?

Sniffer dogs are known for detecting all sorts from illegal substances, but they can also sniff out Japanese knotweed infestations

Sniffer dogs are known for detecting all sorts from illegal substances, but they can also sniff out Japanese knotweed infestations

Knotweed can be hard to spot, is often found in hard-to-access places, and can be buried amongst deep shrubbery. 

Detection dogs can offer the perfect solution to the pesky problem as they are able to sniff out knotweed buried under the ground’s surface without the need to dig, meaning that property owners can avoid extensive excavation in gardens or neighbouring land.

The dogs can identify rhizomes – the plant’s roots and stems – several metres under the ground.  

Detection dogs can offer the perfect solution to the pesky problem as they are able to sniff out knotweed buried under the ground¿s surface without the need to dig

Detection dogs can offer the perfect solution to the pesky problem as they are able to sniff out knotweed buried under the ground’s surface without the need to dig

Such rhizomes as small as a fingernail and can be laid dormant under the soil for a number of years before developing into an insidious knotweed problem.

These pups are light on their feet, are able to access riverbanks, marshes and other tricky spots easier than humans, and also at a greater speed. 

They are able to go out in any weather, during any season. 

The legal implications surrounding Japanese knotweed

Since 2013, property sellers are required to state whether Japanese knotweed is present on their property. 

Sellers: It is the sellers responsibility to check the garden for Japanese knotweed. Sellers must complete a TA6 form, used for conveyancing, which asks for confirmation as to whether the property is affected by Japanese knotweed and, where it is, to provide a plan for its removal by a professional company

Buyers: If the property has Japanese knotweed, it will be stated in the responses to the TA6 form. It may result in the mortage lender requiring assurances that the plant will be eradicated before agreeing to funds. A plan by a professional eradication company tends to be enough assurance. 

Via Daily Mail Science link

Most Popular

To Top