Japanese Knotweed Eradication

Japanese Knotweed presents significant challenges. It is illegal to cause or allow the plant to spread and its presence can complicate property transactions making it difficult to secure a mortgage.  

The plant originated from Japan where its growth is naturally controlled by predators. In Europe and the UK, Japanese Knotweed poses a significant threat and may cause structural issues as it can penetrate cement and clay, causing cracks in the foundations of buildings and walls. Its relentless ability to spread and grow makes it a major concern for property developers and homeowners.  

Conventional methods of eradication, such as the “dig and dump” approach, can be extremely expensive, and require removing not only the plant but also the soil up to 7 meters horizontally and 3 meters vertically from the plant. Furthermore, the excavated material must be transported to a licensed facility, therefore increasing costs. Another traditional option is the “dig and bury” method, which involves containing the plant on-site within an excavated cell line with a root barrier membrane. This solution is the least environmentally friendly and will not have removed the source of the Japanese Knotweed.   

We offer traditional and cutting-edge treatment options to effectively address your issue with Japanese Knotweed. We utilise proven techniques and guarantee the permanent eradication of Japanese Knotweed. All projects are covered by ATG Group’s insurance with a standard warranty that offers a 3-year coverage for a site.  

Our innovative Eraginate® treatment process is the most cost-effective and quickest method to eradicate Japanese Knotweed. Eraginate® revolutionises traditional methods by minimising the amount of material sent to landfill and accelerating the eradication process, resulting in cost reduction.  

With over 130 projects completed in the last 5 years, our experience shows that, on average, the cost of Eraginate® saves our clients at least 60% compared to traditional methods, such as dig and dump.  

Stem injection stands out as an economical treatment option that offers significant cost advantages, especially when time is on your side. This method involves a series of treatments spread across multiple growing seasons, typically spanning up to three years. Its cost-effectiveness and gradual approach make it a compelling option for low-cost, sustainable results. 

Be assured that we possess the skills and expertise required to deliver the best solution tailored specifically to your needs! 

To assist you further, we are pleased to offer a site survey for invasive species in the UK and Ireland, the cost of which will be reimbursed in the event that you appoint us. This survey will result in a bespoke invasive species treatment plan tailored to your specific needs.  

Contact us today to schedule a site survey and let us put an end to your Japanese Knotweed issues!   

Japanese Knotweed Eradication


Our innovative Eraginate® treatment process is the most cost-effective and quickest method to eradicate Japanese Knotweed. This value engineered solution stands as a testament to sustainability. Eraginate® transforms conventional methods by significantly reducing the amount of materials sent to landfill. We achieve this by completing a two-part screening and picking process that separates the Japanese Knotweed material from the soil. We dispose of the Japanese Knotweed plant matter that was picked at an appropriately licensed waste facility and fragment the remaining soils to treat any residual matter plant. The resultant soils are retained on-site, therefore we significantly reduce the volume of material sent to landfill. Moreover, we offer a warranty against the regrowth of the Japanese Knotweed when using Eraginate®. This makes it possible for you to reuse the treated soils on-site, ultimately resulting in cost savings and restoring the natural balance of the environment. 

Dig and Dump 

This process involves identifying and marking the areas impacted by the invasive plant, followed by excavating the soil and then transporting it to a licensed facility. Although this method is quick, the process can be costly and environmentally taxing due to the amount of excavated material, additional transport requirements and often the need for replacement fill material.

Dig and Bury 

Although the dig and bury method is less expensive than dig and dump, it does not remove the liability from the site. This approach involves excavating all the contaminated soil with invasive plants and then burying it on-site. The process starts with the identification and marking of the areas impacted by the invasive plants, excavating the affected soil carefully and burying it at an appropriate depth on-site. This method also requires sufficient space to allow for the excavation of a suitably sized cell to accommodate the Japanese Knotweed-impacted soils. While this method is quick, it can be costly due to the preparation and lining of the cell and disposal of associated soils. Moreover, this method does not remove the contaminated material from the site.

Root Barrier Membrane 

This process acts as a protective shield against regrowth on site boundaries or other areas where removal or treatment is not possible to contain the Japanese Knotweed. By employing this method, we create a mechanism that prevents invasive plants from neighbouring sites from invading the treated area.

Stem Injection  

This method involves cutting the visible plant growth above the soil and injecting our specialised herbicidal mix into the remaining stems. This chemical mixture targets and effectively eliminates invasive plants while minimising environmental impact and collateral damage to the vegetation in the treated area.

Spray Treatment

This technique involves spraying a foliar application onto the invasive plant. Although this method is cheap and stunts growth, due to the time periods involved, we only recommend it for domestic projects.

Person in Charge
Bernard Mullan
Northern Ireland
and Ireland
Duncan Sanders
Cameron Pollock
S-P O'Mahony
Central and
Eastern Europe
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Japanese Knotweed is the scourge of house buyers, sellers and construction companies. Not only does the aggressive invasive species damage foundations, removal can be difficult. It can also reduce the value of houses by thousands.

Tradespeople comparison site HaMuch.com revealed earlier this year that if the perennial weed is found when a house is being sold, it can reduce the value by £23,530 on average!

For construction companies, the discovery of Japanese knotweed can add a massive cost to their projects. Developers who fail to contain the plant on their site could also find themselves prosecuted under the Wildlife and Countryside Act 1981 or the Environmental Protection Act 1990.

It is in everyone’s best interest, therefore, to deal with removal of Japanese Knotweed effectively and sustainably. Traditional ‘dig and dump’ methods impact the environment and are costly as hundreds of tonnes of earth is shifted.

At ATG Group, we have developed our Eraginate® Japanese Knotweed treatment which is more cost-efficient and quicker than ‘dig and dump’ and stem injection techniques. 

To help explain more about the issues surrounding this invasive species, we unravel the roots of Japanese Knotweed…

What is Japanese Knotweed?

Fallopia japanoica, to give it its official name, is a weed that spreads rapidly. The plant dies in winter to ground level but by early summer the bamboo-like stems emerge from creeping underground stems and can grow up to 7ft (2.1m). 

It’s growth is rapid and aggressive, as this Irish Times video shows!

Where did it come from?

Botanist Phillipp von Siebold found the plant growing on the sides of volcanoes, where its growth is kept under control by the climate and regular deposits of ash. Without these impediments, it can grow unabated, which is what is happening in Britain.

After being celebrated in the late 19th century, the Royal Botanic Gardens in Edinburgh began selling it and it became a favourite in large country estates. 

Our Japanese Knotweed expert, Bernard Mullen, explains, “With its ornamental good looks it became popular in country houses, where you often still find it. The landed gentry loved it as it has stems like bamboo, so looked Oriental.”

What does it look like?

In spring, you will see reddish-purple shoots emerge from crimson buds at ground level. The leaves are heart or shovel-shaped and up to 5.5in (14cm) in length and appear in a zig-zag pattern along the stems. The creamy white flower tassels are produced in late summer and early autumn and can reach up to 6in (15cm). Bernard says that its stems look like rhubarb in colour.

What problems does it cause?

The biggest issue with the weed is that it can swamp other plants. It can also grow through concrete and road asphalt. 

Our expert Bernard says, “It can seriously damage foundations, which is why mortgage companies don’t like it. To be fair, it isn’t going to create a Jack and the Beanstalk situation! It won’t pull the house down, but it will eventually create a problem with the foundations if left untreated.”

Legislation and Japanese Knotweed

While it is not illegal to have Japanese Knotweed in your garden, you should control it. Failure to do so could result in prosecution under the Anti-social Behaviour Crime and Policing Act 2014.

Allowing the plant to spread outside your property or in the wild is an offence under the Wildlife and Countryside Act 1981, however. 

You do not have to report the presence of Japanese Knotweed within your property, but you should declare it to estate agents and prospective buyers. Should you choose not to, a buyer could sue you under the Misrepresentation Act.

How can you remove it?

The most popular methods include ‘dig and dump’ and stem injection techniques. They are effective but each type has its drawbacks.

It could cost a developer thousands to dig and dump the affected soil, which also affects the environment. Landfill sites charge a high price as they need a separate area to control its growth. With limited space available, they need to charge a premium.

‘Dig and bury’ on site is another popular method, but while it is effective at removing the weed it restricts the use of available land for development. The other issue is that the Japanese Knotweed remains on site.

Another effective method is stem injection – but this can take around three years to work. So, developers or homeowners may have to delay their plans until they are sure the weed has been dealt with.

Our Eraginate® process

At ATG Group, we are passionate about finding sustainable answers to environmental issues. We have developed the Eraginate® process. It is not only quick, it is more cost effective, which is why so many construction companies and developers choose it.

We can offer an insurance-backed warranty for up to 10 years, so in the unlikely event of the weed returning, we will deal with it within that time.

Our process includes cutting down the knotweed and excavating the roots. We screen the soil and handpick the biggest roots, which are suitably disposed of. We use approved chemicals to treat the remaining knotweed in the soil. Once completed, the remaining soil, which is eradicated of knotweed, can be used on-site as backfill or in gardens and landscaped areas. 

For full details of the process, visit our Japanese Knotweed page.

• If you are a developer or have commercial land that contains Japanese Knotweed, contact one of our experts today

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