Japanese Knotweed Detection Dogs

Lowering property risk with our highly trained detection dogs able to sniff out underground knotweed rhizome

"An ideal solution for any buyer or seller where there is uncertainty as to whether a property is affected by Japanese knotweed."

What are the Benefits of knotweed Detection Dog surveys?

  • Maximum reassurance for buyers and their lender - the most accurate way to determine if a property is affected by Japanese knotweed
  • Enhanced search capability by combining power of human sight with dogs' amazing olfactory (smell) senses
  • Dogs quickly scan the property and “indicate” or show “heightened interest” if the scent of rhizome is detected
  • Results reviewed and verified by our trained knotweed consultant surveyors
  • Removes uncertainty in property purchases and simplifies conveyancing process
  • A "No Knotweed" result optimises the property's value
  • Reduces risk and delays on construction development sites

Research shows a 99% accuracy rate for our knotweed detection dog surveys, making them the most reliable method available for assessing the risk of knotweed presence on a property. A "No Knotweed" result is not therefore a categorical assurance that no viable knotweed is present on the property, although it does entitle you to a discount of up to a 70% on our Platinum Insurance-backed Guarantee (IBG). The IBG gives the reassurance that in the unlikely event of knotweed growth anywhere on the property, the cost of treatment is covered under the guarantee.

Key Details

  • Maximum reassurance
  • Detect hidden knotweed
  • Anytime of year
  • 99% accuracy
  • Instant results

Contact us today to find out more details.

01932 868 700


Follow the Dogs:

We really loved our experience of working with Environet and their excellent highly trained dogs at our client's house in Sussex. We look forward to the next job and will be recommending them far and wide to our clients

Marcus, Trustpilot 5*

When should I get a Knotweed Detection Dog Survey?

A detection dog survey should be instructed where:

  • A seller wants to reassure their buyer that the property is not affected by Japanese knotweed and wants to be sure the information they disclose is correct
  • A seller has ticked “Not Known” on the Law Society's TA6 form and the buyer needs to know whether the property is affected or not
  • A buyer of a new-build property cannot obtain any guarantees from the developer that the property is free of knotweed
  • It is recommended or required by a lender, building society, bank, solicitor or surveyor
  • A property or land is to be developed, as a pre-construction check to ensure no work involving ground disturbance is carried out in affected areas.

They could not have been more friendly and helpful. They did a really thorough job and provided some excellent advice and reassurance. We’re so glad we called them and would thoroughly recommend the service.

Dave, Trustpilot 5*

Call in the Dogs for the Most Accurate Japanese Knotweed Survey on the Market

Labrador Retriever brothers Mick and Mack and Cocker Spaniel rescue dog Buddy have one vocation in life, which also happens to be their favourite game - finding Japanese knotweed!

The trio have been specially trained to detect Japanese knotweed rhizome beneath the ground and there's nothing they love to do more, particularly when they're rewarded with their favourite tennis ball once their work is complete. Dog welfare is of paramount importance so we partnered with RFA Security who are experts in dog training and handling and are fully compliant with BS 8517/2: Code of Practice for Use of Detection Dogs.

Our canine team can cover a garden or development site in a matter of minutes and will indicate by freezing when the scent of knotweed is detected. Exclusively available in the UK from Environet, this is the most precise method available to determine whether knotweed is present and can be carried out at any time of year.

If knotweed is discovered, we will produce a Japanese Knotweed Management Plan detailing options for remedial works. If no knotweed is identified, or suspected, we are able to reduce the cost of our platinum insurance-backed guarantees, saving you up to 70% on the normal price, and giving you complete peace of mind.

Need a Japanese Knotweed Dog Detection Survey?

Call in the Dogs.

Contact Us

I specifically chose Environet for their unique selling point: Mick and Mack. The dogs spent some considerable time investigating every inch of the ground to ensure no knotweed was present.

Mark, Trustpilot 5*”

How can our Detection Dogs help you?

Homebuyers can find out if the property they wish to buy is knotweed-free, giving them the confidence to press ahead with the purchase. This is particularly useful if:

  • the property is located in a high-risk area
  • is situated close to a knotweed infestation
  • is being purchased during winter when knotweed dies back
  • there are suspicions it has been concealed
  • where the seller won't give any assurances e.g. answering “Not known” to the Japanese knotweed question on the TA6 form.

Homesellers can have their property checked, enabling them to provide a high level of assurance to buyers, ensuring there are no nasty surprises further down the line that could disrupt the sale or leave them exposed to a legal claim.

Homeowners can be confident that their biggest investment is protected - and if it's found, remediate the problem as quickly as possible. Those carrying out extensions or landscaping work can proceed with confidence.

Developers and construction firms can progress safe in the knowledge that a site they wish to buy or develop is not impacted by Japanese knotweed and if it is, put in place a suitable remediation plan.

Our Dogs in the Media

As featured on The One Show in September 2022

This is Money

As featured in This is Money on 20th June 2021.

Mail Online

As featured in The Daily Mail on 19th June 2020.

The Times

As featured in The Times on 7th June 2020.

Mail Online

As featured in Country Life on 17th June 2020.

south east today

As featured on South East Today June 2020.

The Telegraph

As featured on ITV News Meridian in June 2022.

The Telegraph

As featured in The Telegraph in September 2021.

BBC South Today

As featured on BBC South Today in August 2021.


As featured in K9 Magazine on 4th July 2020.

south east today

As featured in Your Dog Novemeber 2020.

Q&As with Nic Seal, Founder and MD of Environet UK

We've all heard of dogs being used by the police to detect drugs and the army to detect explosives. Dogs' sense of smell is quite extraordinary and now being put to other uses, such as cancer and COVID detection, and now detection of Japanese knotweed. We caught up with Nic Seal, founder of Environet:

Customers quite rightly want to know if their land is affected by Japanese knotweed. For a long time, we have recognised the difficulty in giving a property or construction site the “all clear” from knotweed, due to the plant's ability to lie dormant for many years. Just because you can't see it above ground does not mean that viable root and rhizome is absent. So about 5 years ago we carried out some research to determine if knotweed put down a “marker” in the soil that could be detected by soil analysis. That proved difficult. But then the light bulb moment happened, and it occurred to us that if dogs can be used to detect things like drugs, explosives and cancers, then perhaps they could detect the odour given off by Japanese knotweed.

Dogs have been used before for other ecological detection but I believe we were first in the UK, in early 2020, to use them specifically for knotweed detection.

Some plants, notably rhododendron and walnut, release chemicals into the soil that are toxic to other plants. It's their form of chemical warfare to keep other plants out of their space that would otherwise compete for water, sunlight and nutrients. It's called “allelopathy”. There is some strong evidence to suggest that Japanese knotweed also does this, explaining why you often find large mono-culture swathes of knotweed. Assuming this hunch to be correct, we thought the dogs would be able to detect it. The real unknown was whether the odour was specific to knotweed i.e. it had a unique signature, which we were happy to discover it had. After all, we wouldn't want them to falsely detect knotweed in a client's prized vegetable garden!

We teamed up with RFA Security, specialists in dog handling and detection. They have a great reputation with explosive detection dogs, where there is little room for error. They use standard methods of fetch and reward, modified where necessary to suit our situation. We now have three beautiful highly trained dogs that are a joy to watch detecting knotweed that is invisible to the human eye.

Typically, they will follow the scent and then when they think they have found the source will stand still and freeze in a position, pointing to the ground with their noise to indicate the exact location. They will remain in the “freeze” position until their handler verifies the indication and praises them with their reward, an old tennis ball. This we call a true positive.

That's a great question which is complicated to answer. When they “freeze” it's relatively easy to verify the result by checking the area and soil for rhizome. I'm pleased to say we have had no false positives.

They may show “heightened interest” but not pin-point an exact location. Depending upon the level of interest that may be classed as an unverified positive, and only time will tell if it is correct.

But the “no indications” are more important when determining the success rate. If the dogs miss knotweed that is visible to the human we know that is a false negative, thankfully that is very rare. But to verify a “no indication” result as true on site is nigh on impossible - the only way we will find out is where we have given the “all clear” and subsequently get regrowth. This has happened in less than 1% of cases and helped us understand the limitations of what the dogs can detect.

Small fragments of knotweed buried at depth will be difficult to detect, but in most cases of undisturbed knotweed the root and rhizomes lie near the surface and can be detected.

It is the odour released by the root and rhizome into the soil that they are detecting. In winter we assume the plant preserves as much energy as it can, hence reducing its chemical warfare capability. We think the odour is weaker in winter so we have a different modus operandiwhich means the survey takes a little longer but still gives excellent results.

When it is very hot, the dogs will be panting, and their concentration and ability to detect will be reduced. We don't expose them to such conditions for obvious animal welfare reasons.

When it is very cold, for example the ground is frozen or covered in snow, then the little darlings are best left in their warm beds and given a well-deserved rest.

That was important to determine in our initial training and was put to the test on several of our sites we have treated. We also tested the dogs by putting dead rhizome (in a state of decay) into test samples and we were pleased to see that the dogs did not indicate. It's an important distinction that gets us closer to verifying whether herbicide treatment has been successful in killing the entire plant, or just making it dormant.

Not all breeds or dogs are suited, but we've found Labrador Retrievers and Cocker Spaniels often have the necessary skills and character traits. Detection dogs need to be intelligent with high ball drive, so a strong natural desire to seek and chase. They also need to be fit and healthy with a well-balanced temperament.

Our research shows that some 5% of all residential property in the UK is affected by knotweed - that's over 1 million properties. The majority, at some stage, will have been treated with herbicide or by other means which can put the plant into dormancy. Dormancy is broken when conditions in the ground change, so knotweed can be present lurking underground but not visible above ground.

Sellers of residential property are required to disclose whether their property is “affected” by Japanese knotweed, and the associated published guidance gives some clues as to what is meant by “affected”. Unfortunately, some sellers blatantly lie or are economical with the truth ending up with lengthy and expensive legal action against them by their buyer. In our research 4% of respondents admitted they would conceal and lie about knotweed to secure their sale - that amounts to a whopping 40,000 misrepresentations each year.

For the honest seller, who is not sure and wants to provide a buyer a high level of reassurance then the dogs can be brought in - we reckon their accuracy rate is greater than 99% and the best available. Unfortunately, we can't give an absolute “all clear” but to minimise risk for the buyer we'll be happy to provide insurance backed guarantees for up to 10 years to cover for any subsequent knotweed growth over the guarantee period.

Buyers can also commission a dog survey to check for knotweed on a property. Where knotweed is found this can be used to substantially renegotiate the price.

In theory yes, as long as the plant has a unique signature.

When they're not working, Mick, Mack and Buddy are taken for long walks in the countryside with the focus on allowing the dogs to simply be dogs, so running, following scents, chasing balls and chewing their favourite toys.

Quite amazing. We are clearly a nation of dog lovers and the media love to feature them. Occasionally we must remind our “dog hugging” customers that the boys are highly trained working dogs and most respect that. Most also respect the fact that cats and in particular on-heat bitches are a distraction and more interesting than knotweed for the boys! Some customers are at first a bit sceptical especially where no knotweed is detected. So, with the customers' permission we may hide a piece of rhizome in the garden and customers are usually mightily impressed when the dog finds it - the find and reward also keeps the dog focused and motivated for the next search.

Absolutely yes, as the demand grows for the service. We started with red-fox Labrador brothers Mick and Mack, with rescue Cocker Spaniel Buddy joining the team soon after. As they prove their worth and with growing awareness of what these fantastic animals achieve, I have no doubt that Mick, Mack and Buddy are the first of many - the original kings of the knotweed detection realm!

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