Articles Features & Opinion Surveys

How did we get into this knotted mess?

japanese knotweed ecology

In this article, Dr. Paul Beckett (Director, Phlorum) looks at the risks surrounding Japanese knotweed and the potential implications for ecologists…

The Japanese knotweed business is booming, yet it has apparently passed many ecologists by.

In completing Preliminary Ecological Appraisals (PEAs) ecologists are not required to audit every plant species on a site, nor, in many cases, is it possible to gain access to all areas. Coupled with the fact that ecologists tend to focus on protected species and habitat with biodiverse potential, discrete stands of vegetation like Japanese knotweed that are to be controlled or eradicated rather than protected, can often be missed. This is despite the Chartered Institute of Ecology and Environmental Management (CIEEM) guidance, which states that in carrying out surveys, ecologists should consider the contravention of laws preventing legally controlled plants, like knotweed, from spreading.

Knotweed isn’t just a nuisance in the UK; it covers swathes of North America and Western Europe, causing similar problems as it does here. However, the UK is unique in the way risk of knotweed damage to property is perceived, and in the existence of a mature and professional knotweed control industry.

This article presents a short history of the knotweed industry in the UK and offers insights into why it has perhaps been a missed opportunity for many ecologists. Going forward, it highlights why ecologists need to be aware of the risks, no matter how ridiculous they might seem.

© Phlorum

© Phlorum

How did it get here?
Japanese knotweed was first planted in the UK around 1825 at the Horticultural Society of London’s Chiswick garden (originally from China, with Japanese samples arriving 20 years later). Cuttings were later shared with other botanic gardens across the UK, during which time it was realised that it had the potential to spread at an alarming rate and be very difficult to eradicate.

One of the first records of knotweed in the wild is described in The Flora of Cardiff (1886) where it was reported as being “very abundant on the cinder tips” near the town of Maesteg, South Wales . Coincidentally, this is the same village that was subject to a landmark knotweed court ruling over 100 years later, in 2017. This court case exemplifies the concern and risk to property that knotweed can currently cause – more of this later.

Knotweed and contaminated land
The UK was quite far ahead of most other countries in recognising the potential impact of invasive non-native species (INNS) such as knotweed, in as much as it was listed in Part 2 of Schedule 9 of the Wildlife and Countryside Act 1981. This made it an offence to cause knotweed and other INNS plants to spread into the wild. However, it was not until the contaminated land regime kicked in during the late ‘90s (Part 2A of the Environmental Protection Act 1990), that knotweed was recognised as a potential property risk.

As part of the due diligence process on land transactions and property development proposals, the regime required land contamination risks to be identified and, if necessary, remediated. By this process knotweed was quickly recognised as a contaminated land risk, requiring remediation, and it slipped into environmental tax relief schemes originally aimed at more conventional ground contaminants like heavy metals and hydrocarbons.

© Phlorum

© Phlorum

I can’t sell my house!
This awareness of knotweed as a land risk amongst property professionals spread further along the property transaction chain. This resulted in due diligence and valuation surveyors for the major lenders, reporting it in their surveys as a potential risk. The lenders then sought to understand this risk by seeking remediation solutions from the growing number of knotweed control firms. However, as an unregulated group, having expanded from a wide range of service providers from ground workers to amenity horticulturalists, the advice and costs quoted for mitigation were far from clear.

The plethora of costs and treatment options made it impossible for lenders to reach clear decisions on the risks posed. Therefore, very quickly, lenders began refusing to accept any risk on land affected by Japanese knotweed. Consequently, in the late ‘00s it was almost impossible to secure mortgage finance on knotweed affected property. This was particularly the case for domestic homes, where the high number of relatively low return transactions and banks’ likely reticence to release funds during a recession, hit homeowners and first time buyers particularly hard.

© Phlorum

© Phlorum

The knotweed control industry grows up
Seeking a resolution to this problem, the lenders’ trade bodies (namely the Council of Mortgage Lenders and the Building Societies Association) approached a select group of knotweed control companies and requested them to do the following:

  • Produce guidance for property professionals on how to identify the risks posed by Japanese knotweed; and
  • Form a trade body of knotweed control companies that are able to offer treatments that will satisfy lenders’ risk requirements.

With a great deal of organisation and work, this was done. First, an information note was produced through the Royal Institution of Chartered Surveyors (RICS) that laid out a framework for property surveyors to identify Japanese knotweed and to determine whether or not the services of a professional knotweed treatment firm might be needed. And secondly, a knotweed trade body was established under the umbrella of the Property Care Association, which was well placed in this role as it had sorted out the damp-proofing industry some 20 years earlier, which historically was similarly affected by a lack of organisation and numerous rogue traders.

It is important to note at this point that the aim of the guidance and formation of the trade body was to calm everyone down about the actual risks to property caused by knotweed. Re-reading the RICS guidance and the Property Care Association’s (PCA) Code of Practice for controlling knotweed, it is stated several times that knotweed rarely causes structural damage. In fact it is much less of an issue than the damage that can be caused by some trees to a building’s foundations in shrinkable clay soils; or damage caused by other vigorous woody species like buddleia and ivy, which can, over time, exploit cracks in structures, prising them apart as the plants grow.

The efforts of the RICS and the PCA proved a success. Almost immediately lenders began to use the guidance and the services of accredited knotweed control firms, such that risks were effectively managed and mortgages on knotweed affected properties were offered. Hooray!

Property blight
However, perhaps as a victim of its own success, the sudden increased awareness of property professionals to knotweed risk was misinterpreted by some. In its first few days of release, the information note was downloaded over 8,000 times and it remains the most downloaded RICS note ever produced. In response to the guidance, property surveyors redoubled their efforts to consider knotweed risk and protect themselves from potential liability issues. This probably attracted media interest and unscrupulous contractors, in whose interest it was to publicly promote knotweed as a property pariah.

It was quickly becoming evident that even if a surveyor did not notice knotweed on a property, it might still be noticed by vigilant members of the public. In fact a news article from 2015 reports how a builder was arrested in south London after a dog walker spotted him working amongst knotweed.

Instead of providing a solution to knotweed’s impact on property, the raised awareness of it resulted in panic. Whereas in the past knotweed’s ubiquity in urban areas and its relative harmlessness meant that it could go unnoticed, it was now much more likely to be identified during the initial stages of a property transaction. Coupled with purchasers’ skewed perception of knotweed risk, this blighted property and made it less desirable.

Lenders responded to the market hysteria by again refusing to lend on some properties affected by knotweed. The RICS information note provided them with a handy sliding scale of risk from categories 1, low risk, to 4, highest risk. This caused some lenders to elect not to lend on Category 4 properties, much to the chagrin of the RICS note’s authors – as the intention from the outset was for the guidance to allow lending against all knotweed risk and not to allow some transactions to be blocked.

Knotweed-affected property was less desirable and thus became harder to sell. This had a knock on effect of diminishing property value, which is a very big deal, particularly to homeowners whose investment in their property is their single greatest outlay.

© Phlorum

© Phlorum

Enter the lawyers
The large damage costs associated with knotweed on property, resulted in a sharp rise in legal action. People buying property who were not aware of the costs it could impart, were issuing claims due to the non-disclosure of knotweed’s presence.

The Law Society recognised the problem and added a question on knotweed to their TA6 Property Information Form, which is used in the majority of residential property sales. This asks a Yes/No question about whether knotweed is present on a property and is intended to manage and disclose risk during a sale. With many homeowners not being aware of the potential consequences, the “No” box was ticked without proper thought in many property transactions.

This, along with the range of potential liabilities in the transaction process between vendors, surveyors, conveyancers and neighbouring properties, enabled lawyers to form arguments and strategies that allowed them to make substantial damages claims.

Which brings us back to Maesteg. In February 2017 a judgement was made against Network Rail Infrastructure for allowing Japanese knotweed to accumulate on land adjacent to two bungalows in the village, which caused their values to be reduced.

Most knotweed cases are settled between the parties before court and are not therefore publicly disclosed. However, the Maesteg case went all the way to court and the resulting judgement set an important precedent, which is now fuelling other litigation cases.

© Phlorum

© Phlorum

What next for ecologists?
So the real impact of knotweed, and perhaps other INNS, seems to have simply become the public’s perception of harm causing a blighting effect on property value. But what does this mean for ecologists? They should certainly be alive to very real risks posed by knotweed, particularly in areas such as towns and villages.

The law is a vital means of recourse where innocent property owners are subject to potentially substantial damages, such as loss in value of their homes. However, with this perhaps comes a risk of less scrupulous claimants or lawyers hungry for new business to exploit the precedents and push for unreasonably large damages.

Ecologists may increasingly find themselves on the wrong end of such claims. It could easily be the case that pockets of knotweed growth on a large site of marginal land on the edge of a town could be missed during what would otherwise be an unremarkable PEA. Who then covers the costs of dealing with the unplanned expense and/or increased knotweed liability for the landowner when these plants are eventually discovered? The finger of blame will be seeking out a prospective target that could ultimately be the ecologist who missed the knotweed, or other INNS, during their PEA site walkovers.

It is therefore very important that ecologists appreciate what risks they might be exposed to and for them to take the necessary steps to ensure that their liability is protected. In terms of opportunity, this could mean that a market has developed for specific INNS surveys, the liabilities for which could easily exceed the fines and other costs associated with negligence claims for protected species like bats and reptiles.

Is this crazy? Perhaps. But until the public can be reassured that the perceived risks espoused in the media bely the actual physical harm caused by INNS, such as knotweed, the lenders and lawyers will not follow suit and we will be no further forward in these crazy times.

Header Image: © Phlorum

About the Author: Dr. Paul Beckett is a founding director of Phlorum, a multi-disciplinary environmental consultancy that was established in 2003 on the basis of providing common-sense solutions to the burgeoning problems caused by Japanese knotweed. His background is in plant ecophysiology and he is a member of CIEEM. In 2012, Paul helped produce knotweed guidance for the RICS and was part of the working group that established a trade body for knotweed and INNS professionals, the PCA Invasive Weed Control Group (IWCG). He is an experienced expert witness, having represented a variety of professionals and property owners involved in cases where knotweed affects property. This includes acting for the claimants in the landmark Waistell & Williams v Network Rail case in Maesteg, South Wales.