Over the last decade, Japanese knotweed has developed a reputation for being one of the most aggressive, invasive plants to be currently blighting the country. However, despite the plant’s fearsome reputation, there can still be some confusion as to what it actually does. This article will explain what Japanese knotweed does from two perspectives: environmental and financial. The examples cited here should be considered within the larger context of Japanese knotweed cases, this plant can thrive in all sorts of environments, but no single infestation is the same.

What are the environmental impacts of Japanese knotweed?

Japanese knotweed has a number of physical characteristics which has made it particularly troublesome in the UK, chief of these is the incredible speed that it grows at. Whilst it does die back during winter, its peak growth during the summer can see it growing up to 20cm a day and 1.5 metres in the space of a week. Coupled with its incredible resilience, it’s unsurprising that the government has labelled Japanese knotweed as an invasive threat

Not only does Japanese knotweed grow fast, but it also spreads at an alarming rate. Although the plant does not propagate in the usual fashion in the UK (only the female of the species was imported to Britain in the 19th century), it spreads via an underground root system, comprised of rhizomes. Not only are these roots fast-growing, but they’re also capable of growing from the smallest of fragments, which was one of the driving factors behind the government making it a criminal offence to move soil that has been contaminated with the plant.

Unfortunately, despite the control measures that have been put in place, the spread of Japanese knotweed has continued to the point where the plant is estimated to an infestation for every 10 square kilometres in Britain, according to PlantTracker who produced data that helped build a map showing the spread of Japanese knotweed in the UK.

How deep are Japanese knotweed roots?

Japanese knotweed roots can develop a system that burrows up to 3 metres deep underground and a further 7 metres horizontally from where the plant breaks ground. The depth and complexity of this root system make it a difficult and costly task to remove completely. Whilst digging out the plant is considered to be one of the most effective methods of eradicating Japanese knotweed, the cost and disruption of doing so can be prohibitive to some.

Does Japanese knotweed smell?

Japanese knotweed does not have a particularly distinctive smell. Its scent is not considered to be one of its defining features and does not contribute to its undesirable reputation.

Is Japanese knotweed dangerous?

Japanese knotweed is not poisonous, nor does it pose any physical danger to animals or people. The plant does, however, pose a threat to native plants that are not as well equipped to compete with this foreign element. The environmental impact that this plant has on our own wildlife is often overlooked in favour of the financial costs of treating it. When the plant is allowed to thrive on public waterways or on disused industrial lots, it can quickly stifle the growth of any other plants growing nearby.

What are the financial impacts of Japanese knotweed

Setting aside the environmental impact of this invasive species,  an infestation can have serious financial implications for all involved. Homeowners discovering Japanese knotweed are faced with the knowledge that the value of their home will almost definitely depreciate. Developers who want to build on land with Japanese knotweed may have to completely redraw their plans, as they might have to pay for the complete removal of the infestation before they can go ahead with any construction. For example, plans for developments, in the lead up to the London 2012 Olympics, were delayed when a massive infestation was discovered on the proposed land. Teams spent four years getting the weed under control.

Perhaps most frustratingly, Japanese knotweed infestations can lead to wasted time and the collapse of property chains, which come with their own set of financial pitfalls. For example, often a prospective buyer may spend hundreds of pounds on surveying a property, under the impression that there is no Japanese knotweed present (according to the TA6 property form). On discovering a significant infestation and not wishing to take on the responsibility that comes with treating it, the buyer may drop out of the purchase, but there will be no legal recourse for them to recover the money that they spent on the survey as no form contract would have been signed.

All told, Japanese knotweed is estimated to cost the UK economy £166 million per year for treatment and in property devaluations.

What does Japanese knotweed do to a house?

Japanese knotweed does not necessarily ‘write off’ a house. How the plant affects the property will depend on the severity of the infestation and how close the plants are to the buildings. Although it’s possible to find evidence of Japanese knotweed literally breaking through into homes, this is rare and usually the result of a combination of poor building maintenance and a particularly aggressive infestation. Japanese knotweed’s predominant effect on a house is financial. In the average case of Japanese knotweed discoveries, the value of the property is diminished between 5-20%.

Can Japanese knotweed grow through concrete?

There is some photographic evidence to prove that Japanese knotweed can grow through concrete, however, this has only been noted to happen in scenarios where the infestation is particularly bad and the construction work is particularly shoddy. In extreme cases, Japanese knotweed is also know to disrupt independent structures such as garden sheds, greenhouses, fences. The plant can also slowly break through shoddy brickwork, paving and tarmac.

Can Japanese knotweed damage foundations?

It’s possible for Japanese knotweed to damage the foundations of a house, but this will only happen when infestations are long-established and there are already weaknesses in the building. In very rare cases, Japanese knotweed has been known to break its way through floorboards and skirting boards which can lead to a house being unsellable, as in the case of the Joneses in Broxbourne who were recommended to demolish their entire home. Their property’s value plummeted from £350,000 to £50,000 – a rare example but one which has had an impact on the industry at large.

Can you sell a house with Japanese knotweed?

It is legal to sell a house with Japanese knotweed, however, the invasive plant’s reputation often makes it difficult to sell up when the time comes to it. If you’re attempting to sell a property with Japanese knotweed then you should state that the property has been affected on the TA6 property form. Similarly, if you’re aware that the land has been treated at some point, even if the knotweed has died off, you should still mention it. Failing to mention or lying about your property being affected by Japanese knotweed could lead to a misrepresentation claim being brought against you.

Can you get a mortgage on a property with Japanese knotweed?

You can get a mortgage on a property with Japanese knotweed, but most mortgage lenders will first ask to see evidence of a knotweed management plan being in place. This plan will prove that you have hired a PCA-accredited removal firm to manage the removal of the plant, and will also be insurance backed, so that in the event that the firm goes out of business before the plan is complete, another company will carry on the work. Although some lenders have relaxed their stance on Japanese knotweed, there are some that still refuse to give mortgages for properties affected by it. Re-mortgaging properties that have recently become infested can also be difficult, depending on the lender that you’re dealing with.

Finally, a Japanese knotweed infestation can also be the root of tension and conflict between two parties, whether they’re neighbours, or strangers attempting to negotiate a sale. Due to the potential legal complications that can ensue from the discovery of Japanese knotweed, the plant can also be responsible for undue stress and pressure as individuals attempt to fight their corner without the legal help that they need to succeed. Without legal aid, parties can quickly become trapped in a frustrating back and forth with councils or organisations, this time wasted can only add to the pressure as both parties are aware that whilst the discussion is ongoing, the infestation is being allowed to continue growing.

If you’ve discovered Japanese knotweed on your land, or are currently locked in a dispute related to it, then we may be able to help. Give us a call or send us a message using the contact form, and we’ll get back to you with guidance on how best to proceed

Freephone 03335 777 888

The internet is filled with masses of information regarding Japanese Knotweed, and some of it can be particularly frightening. We receive dozens of phone calls every day, and many people as us to debunk myths that they have read online. Here are some of the most common, and why they are incorrect.

“You kill Japanese Knotweed by cutting it down and pouring bleach into it”

There are many different versions of this one using various different substances, but the answer to them all is no. The only substance we know to kill Japanese Knotweed is a glyphosate-based herbicide. Unfortunately, the herbicides which are available to the public are also not strong enough to do the job. The herbicide experts will use is 300x stronger than anything available for purchase by the public.

“You cannot get a mortgage on a property if it has Japanese Knotweed”

We receive many panicked telephone calls from people on both sides of the purchase who believe this to be true, but worry not, because we can help. We can support your enquiry with a Site Survey and Management Plan by an accredited firm, coupled with an insurance backed guarantee. If you have these documents in place from an accredited company, mortgage lenders will typically release the funds.

“Japanese Knotweed can break through concrete”

There are many horror stories littered across the internet regarding Japanese Knotweed, often about its strength and the damage it is capable of doing. Japanese Knotweed cannot break through a solid piece of concrete in a normal way. It will, however, seek out any cracks or weaknesses in any structure, and many properties will have small cracks or movements below ground caused by various things including subsidence and foundation settling. Like all plants, Japanese Knotweed seeks light when underground. Its rapid growth means that a small piece could find its way through a crack, and then push it open as it grows.

Japanese Knotweed is not a superhero, but should still be taken seriously.

Japanese Knotweed growing on a property based in Bristol has been the cause of a property firm being indicted with a hefty fine. The Japanese Knotweed affected 7 properties and Bristol City Council prosecuted MB Estate Limited which owned the offending property.

The presence of the Japanese Knotweed was not highlighted in house surveys undertaken by the owners of the affected properties, even though the plant was thought to be reaching 8 foot. Unfortunately for the buyers, they were unaware of the adverse effects Japanese Knotweed could cause on their properties and it was only when one homeowner Googled the plant that the severity of the situation became clear.

When the Anti-Social Behaviour, Crime and Policing Act 2014 came into effect, it was only then the local council were able to take action against the property management firm. The firm had various opportunities to take steps to remediate the invasive weed and unfortunately did not take adequate steps to prevent the legal action to be taken against them.

With cases such as Waistell v Network Rail making headlines recently, it has set a precedent for other homeowners who are affected by the troublesome weed that there are cautions in place to ensure encroachment does not occur, and where it does, redress through legal channels is now available.

Getting lost in the legal jargon which is thrown at you once you instruct a legal professional is a rabbit hole too many of us take a trip down, make sure you know what a Part 35 report is and when you might need one.

Generally, Japanese Knotweed disputes are easily resolved once an individual takes responsibility for the presence of the weed and ensures that it is eradicated in line with the specific rules and regulations put in place. However, in some circumstances where the origin of the Japanese Knotweed is harder to determine, or in situations where the landowner is denying liability, you may need to consult your solicitors on the best way to proceed down the legal route.

Japanese Knotweed is classed as a ‘Schedule 9’ plant and in relation to this, Section 14(2) of the Wildlife and Countryside Act 1981 states that “if any person plants or otherwise cause to grow in the wild any plant which is included in Part 2 of Schedule 9, he shall be guilty of an offence”. Due to this, we see time and time again, instances where individuals have taken legal action against landowners who have allowed this highly invasive weed to encroach onto their sites.

Typically, your solicitors will firstly arrange for an initial vetting report which will give them the basic details of the Japanese Knotweed they will need to know before being able to decide as to whether or not the case can be taken to court. Once they have the initial vetting report, this is usually when solicitors will arrange for the P35 Report.

Part 35 Compliant Reports are specific documents which answer the questions solicitors will need to know and use in their court case. Typically, these P35 reports are used to determine the cause of the origin of the Japanese Knotweed and therefore pin liability to the correct person. P35 Reports are usually taken around a week to compose due to the in-depth analysis required to fully investigate the situation at hand. If you are not proceeding down the legal route, you usually won’t require this service.

It is important to know that the Part 35 writer has a duty to the Court and not to the person paying for or requesting the report. A Part 35 report writer will know that their duty of being correct is to the court and anything other can be seen as contempt of court.

What the Waistell vs Network Rail case means for you…

We have all heard about the landmark Japanese Knotweed case of Mr Waistell v Network Rail, but what exactly was the precedent which was set following the hearing?

Japanese Knotweed was typically used by Network Rail to stabilise railway embankments in the past, and due to this, most railways in Britain are dotted with stands of the invasive weed. Unfortunately for Mr Waistell, his property backed onto one such area. Although there was no Japanese Knotweed growing on Mr Waistell’s property, it was in such close proximity, so as that his solicitors were able to argue that it was interfering with “quiet enjoyment of the property”. This shows us that if there is a premise for Japanese Knotweed to spread onto your property, you have some legal standing.

If you do find yourself in a situation where there is Japanese Knotweed growing within close proximity, we would always advise initially getting in touch with a Japanese Knotweed remediation company as they will be able to come out and conduct a survey for you to get a more detailed insight into the situation at hand.Following the survey, the company should be able to provide you with a management plan to eradicate the Japanese Knotweed. Depending on the extent of the Japanese Knotweed, you may not be prepared to pay for these costs, and this is when getting in touch with a legal professional will come in handy.

If you think there is Japanese Knotweed growing on your or a a neighbouring property or site, please feel free to get in touch with us on freephone 03335 777 888

Your home is your castle. Eradicating Japanese Knotweed in Cheshire. And if you are particularly house proud, you will know that the outside of your home is just as important as the interior. So, what should you do when you notice Japanese Knotweed growing in the property next door?

Ideally, you will get in touch with the neighbour initially to see if there is an eradication plan in place. Once you know the status of the offending plant, you should be able to then decide your next steps on how to proceed.

If there is a management plan in place, there’s no need to worry as the neighbors are adequately dealing with the problem. If not, there a few options you can explore:

Arrange for a Japanese Knotweed professional to come out and assess the situation: by doing this you are able to determine as to whether or not the Japanese Knotweed will affect your property directly. They will then be able to advise of any recommendations they may have with regards to your property.

Get in touch with the Environmental Agency: if the Japanese Knotweed has spread over into your garden, your neighbour is liable to pay for the costs of remediation. This is because although it is not illegal to have Japanese Knotweed growing on your property but it is illegal to allow it to spread, and by doing so, your neighbour may be faced with a fine of up to £2,500.00 plus the remediation costs!

Take out your own management plan: with your neighbours permission, it may prove easier to take out a management plan yourself for the remedial work on their property – this would be the best situation if you are looking to sell your property, as many mortgage lenders will refuse to allow funds against a property which has Japanese Knotweed growing within 7m of the boundary. This is obviously a last resort and you may need to decide whether or not the sale of the property is worth the treatment cost.

If you think you may have Japanese Knotweed growing on your property, speak to the experts! Get in touch today! Call the Japanese Knotweed Agency on freephone 03335 777 888

Japanese Knotweed is a nuisance plant that can set back house sales, cost homeowners thousands in removal costs and hours of precious time in settling legal matters. Whether it is growing in your neighbour’s garden, or you’ve just bought a house with Japanese Knotweed, it’s likely that you’ll want to find out as much about this foreign invader as possible, and it’s not unreasonable to wonder whether this much-maligned plant could cause you or your family harm.

Is Japanese Knotweed poisonous?

Despite its fierce reputation, Japanese Knotweed is not poisonous. Although the plant is an incredibly quick grower and can prove to be a resilient enemy for homeowners, it does not contain any poisonous element, unlike other plants that are featured on Schedule 9 of the Wildlife and Countryside Act 1981.

Is Japanese Knotweed harmful to humans?

Japanese Knotweed is not harmful to humans, although some have reported that contact with the plant can cause some mild skin irritation. Japanese Knotweed is often confused for Giant Hogweed, which does pose a real threat to people. Giant Hogweed’s sap can irritate the skin, causing blisters, rashes and even blindness. For that reason, it’s a good idea to make sure you positively identify Japanese Knotweed before handling it in any way.

Is Japanese Knotweed poisonous to pets?

Japanese Knotweed is not poisonous to pets. There are many plants that could cause harm to your pets, but Japanese Knotweed is not one of them. Common house pets such as cats and dogs are unlikely to take a bite of the plant, but even if they do, they shouldn’t come to any harm as a result.

Can animals eat Japanese Knotweed?

Grazing animals, such as goats, can eat Japanese Knotweed however, farmers should seriously consider this option before allowing their herd to do so as animal consumption could lead to undue dispersal of the plant. Japanese Knotweed is a unique invasive plant as it is too cold for the plant’s seeds to properly germinate in the UK. The plant multiplies via its rhizome system which can reproduce from the smallest of fragments. Allowing animals to eat Japanese Knotweed could further disperse these rhizomes and exacerbate the infestation.

Can people eat Japanese Knotweed?

It is possible for people to eat Japanese Knotweed, however, there are some risks inherent in doing so. Some plant foragers have identified the best times of year to harvest the invasive plant, however, this must be done with caution. The plant is said to be edible as a young tender stem during the months of April and May. As the plant matures, the stems toughen and can cause abrasions in the mouth. Although there is a wealth of recipes online, it’s worth noting that there are few specific health benefits associated with eating it, other than as a herbal treatment for Lyme Disease and a means to lowering cholesterol.

In the event that Japanese Knotweed is harvested for consumption great care should be taken to ensure that the plant has not already been chemically treated. Those intent on foraging Japanese Knotweed should also ensure that they do so within the law pertaining to Japanese Knotweed. It is an offence to cause the spread of the plant and those who are found to do so could be fined or even imprisoned. Make sure you fully understand the legal implications of handling Japanese Knotweed before planning a foraging trip.

What does Knotweed taste like?

Botanist and columnist James Wong has reported that Japanese Knotweed has a similar ‘bright and tangy flavour’ to rhubarb and noted in his article for the Guardian that it can be served in a variety of ways including desserts, such as crumbles, or as a chutney or sauce with cheese or meat. Foragers have noted that is has a lemony flavour and can also be used in the creation of wine or beer.

Japanese Knotweed is not poisonous, but whilst eating the plant is certainly possible, it’s by no means the most effective method of removing it. Getting rid of Japanese Knotweed is best managed with the help of an experienced firm and an insurance-backed PCA-accredited treatment plan.

For more information and support contact the Japanese Knotweed Agency on freephone 03335 777 888

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Following the recent review of the EU Invasive Alien Species (IAS) Regulations, the Property Care Association (PCA) released a statement that 17 new species are being added to the list of ‘Species of Concern’ – 13 of which are plants (You can see the full list here).

This regulation contains species whose potential adverse effects across the European Union are such that concerted action across Europe is required to control them. The list is drawn up by the European Commission and managed with the Member States using risk assessments and scientific evidence. The regulation should not be confused with UK invasive alien species legislation. The GB Non-Native Species Secretariat (NNSS) has information on UK invasive alien species legislation here.

The IAS Regulation 2014 provides for three distinct types of measures to control ‘Species of concern’:

Prevention: measures aimed at preventing the introduction of IAS into the EU (e.g. restrictions on sale and supply via the horticultural trade).

Early detection and rapid eradication: Members must put in place a surveillance system designed for ‘early detection’ and take rapid eradication measures to prevent establishment.

Management: If already established, implement a management plan to prevent them spreading further and minimize the harm they cause, ecological or otherwise.

The PCA have reviewed the new plants considered “of concern” and have identified the following 3 plants, as most likely to enjoy the UK climate.

The Tree of Heaven

The Tree of Heaven (Ailanthus altissima) is already included in the PCA’s useful guide on the Practical Management of Invasive Non-Native Weeds.

Although it originates from East Asia, it arrived in the UK as a horticultural introduction in 1751. It’s prevalent in the south-east of England, especially Greater London and East Anglia. It’s mainly restricted to the urban environment where it forms thickets of inhibiting ground flora, both by shading and through the production of a toxic chemical that suppresses germination and growth of other plant species (so-called allelopathy). Roots and suckers can disrupt structures, pavements, drains and buildings, leading to it being coined “Tree of Hell”.

The Balloon Vine

The Balloon Vine (Cardiospermum grandiflorum) is a climbing shrub that is already classed as invasive in Australia, South Africa and Southern States of the USA. It was introduced around the world mainly as an ornamental plant. It escaped cultivation and became naturalised and invasive. Once established, it grows rapidly into the tops of trees, forms a thick curtain of stems, excluding light, and harbours pests and diseases. Weight contributes to canopy collapse and ecosystem destruction. C. grandiflorum is a declared noxious weed in Australia and South Africa, is reported as invasive in many other countries, and is likely to spread. This is something to look out for; there are no UK NBN records so far but one CABI record in France. It’s associated with drier climates/soils, so global warming might increase the likelihood of arrival here especially in frost-free areas.

Japanese Hop

Japanese hop (Humulus japonicus; Humulus scandens) hails from temperate-climate regions of Asia (China, Japan, Korea, Taiwan and the Russian Federation) and tropical Asia. It’s another plant already listed as invasive in North America. Like all ‘hops’ it is closely related to cannabis but unlike the common hop is absolutely no use for making beer at all (just in case you were wondering….).

Japanese hop can spread to cover large areas of open ground or low vegetation including understory shrubs and small trees. Many thousands of hop plants per acre may be produced, eventually blanketing the land and vegetation. The vines grow rapidly during the summer, climbing up and over everything in their path and can form dense mats several feet deep, blocking light to plants underneath. Hop vines also twine around shrubs and trees causing them to break or fall over. It is invasive in riparian and floodplain habitats where it displaces native vegetation prevents the emergence of new plants and kills newly planted trees installed for streamside habitat restoration. Hop can quickly cover small trees hiding them from view, preventing mowing and obstructing herbicide applications.

The government has recently confirmed that the Invasive Alien Species (Enforcement and Permitting) Order 2019 will bring EU legislation into UK law on 1 December 2019.

Lord Gardiner, the Biosecurity Minister said:

“Invasive non-native species not only challenge the survival of some of our rarest species but damage our natural ecosystems as well as costing the economy more than £1.7 billion per year.”

“The law requires management measures to be put in place and this consultation will ensure we consider the evidence on how best to manage these species of concern.”

The government say that the UK will continue to uphold international obligations and as a responsible partner nation working closely with other countries to protect our native wildlife and forestry landscapes for future generations to enjoy.

Here at Japanese Knotweed Ltd we survey, manage and control a wide range on non-native invasive species and keep track of changes to relative UK & EU law, monitoring how it may affect us and our clients.

Call us freephone 03335 777 888 or send us a message through our contact us page.