Consultancy and Surveys

There’s something about Japanese knotweed that provokes sensationalism, exaggeration and misleading untruths. It can often be difficult to sort the fact from the myth.

We at The Knotweed Company believe knotweed can be impressive enough without ‘over-egging the pudding’ and we see no benefit in frightening people with misinformation. Therefore we are committed to providing ethical, straight-talking and factual advice and guidance to our clients, all of which references codes of practice and information papers produced by such organisations as The Environment Agency and the Royal Institute of Chartered Surveyors. In addition we are members of the Property Care Association and work closely with them to ensure our practices and advice are completely up to date and that we comply with their code of practice.

We offer a range of consultancy services. See below (or click on the links to go directly) for:

In addition to the above, we can provide CPD and corporate presentations on knotweed issues and treatments (or presentations on other invasive weed-related subjects). Our staff has provided such presentations to a wide range of clients, including RICS, County Councils, property management groups, mortgage providers and environmental consultants.

If you require a specific service that has not been listed here or anywhere else on our website please e-mail us with your requirements and we will let you know how we can best assist you.

Property Risk Surveys / Verification Surveys

Around 2008/2009 mortgage providers adopted a fairly rigid approach to lending money for properties with Japanese knotweed within, or close to, its boundaries. This led to many struggling to sell their properties if knotweed was present. Since 2013/2014 the situation has improved. Thanks in no small part to the advice of industry professionals such as the PCA, the Council of Mortgage Lenders (CML) have advised their members to adopt a more flexible and individual approach. While this has led to a number of High Street lenders becoming more open to lending on knotweed-affected properties there are still a number of lenders, as well as mortgage advisors, who have remained unyielding on this issue. Even if no mortgage is involved, some purchasers have shied away from purchasing a property because they believe the knotweed will be too much trouble, too much of a risk or too expensive to deal with. There have even been property sales that have fallen through due to a surveyor or other interested party erroneously identifying a completely innocent plant as knotweed.

To help smooth the course of property sales we offer a range of advice and survey services.

Verbal advice

We are happy to discuss your site over the telephone and provide whatever advice we can from the information we are supplied. We can also meet you on site to discuss matters in more detail but we may have to make a charge if a site visit is involved (depending on location and timescale).

Verification Survey

The first crucial step on any site, whether it is a residential or commercial property subject to a sale of ownership or land awaiting redevelopment, is to verify the presence or non-presence of Japanese knotweed. As part of our verification service we carry out a site survey and issue a brief report if no evidence of knotweed is found. If knotweed is discovered on site, we recommend upgrading to a full Property Risk Survey (see below). A Verification Survey can also be a useful means of side-stepping issues caused by a building surveyor mistakenly identifying another plant as knotweed, or by the surveyor muddying the waters by stating in their report that knotweed ‘may’ be present.

If you have a plant in your garden you suspect is knotweed but are unsure you can e-mail us photographs of the plant on and we will provide a free of charge assessment on the identification of the plant in question. Please try to limit the file size of the photographs to prevent difficulties in our receiving them.

This service is also available for surveyors if they identify something they think might be knotweed but are not sure. It is better to find out than to delay a property sale due to highlighting ‘suspected’ Japanese knotweed in a survey that is later discovered to be nothing of the kind.

Property Risk Survey

The purpose of this survey and report is to provide clear information and guidance for mortgage lenders, purchasers, vendors or any other interested party. The report will clearly map the location(s) of the knotweed, quantify the level of risk the knotweed presents (in accordance to the guidance provided by the RICS information paper ‘Japanese knotweed and Residential Properties’) and provide recommendations for managing and eventually eradicating the plant as appropriate to the individual site.

Please note that there is a limitation to any kind of visual survey. It is impossible to prove a negative – i.e. it cannot be categorically stated that a site contains no knotweed, merely that there is no visual evidence to suggest it is present on the site. This is because if knotweed has been accidentally or deliberately cut down, partially dug up, covered over, been subject to something strong enough to temporarily halt its growth or if there are any other factors involved that would cause viable knotweed rhizomes to retreat into temporary dormancy, there may be no visual indications of its presence.

Watching Brief

In some circumstances a knotweed excavation may be planned where suitably experienced plant operators and other personnel will already be present on site and can be utilised for the operation. In other circumstances some development work (e.g. erection of a conservatory, installation of drainage, scheduled landscaping works, etc.) may be planned by others that will infringe close to visible knotweed. In both these circumstances it is important to have someone on site who understands how knotweed grows, the legal implications of disturbing knotweed material, the importance of employing proper site hygiene management and who is capable of identifying knotweed material in the soil.

The Knotweed Company can provide trained professional staff who can either offer advice and guidance to site personal or supervise the whole operation to ensure that knotweed material is not disturbed and, if it is, that it is contained and properly disposed of without spreading contamination elsewhere.

Knotweed Management Plans

A Knotweed Management Plan (KMP) is a document detailed extensively in the Environment Agency Knotweed Code of Practice, where it is described as “essential” on a development site where knotweed is present. The Code of Practice calls the KMP “an important document [that] provides a valuable record of the treatment of the site for future owners.” Though the Code has now been withdrawn and is no longer updated by the EA, it remains an essential document for describing best practice.

The principal purposes of a KMP are:

  • To clearly identify the extent and location(s) of Japanese knotweed on site, and in adjacent areas where the threat of the knotweed spreading across the site borders is high
  • To establish the best means of dealing with the knotweed
  • To ensure all site staff are properly educated as to what knotweed looks like and to understand the consequences of disturbing the plant
  • To put in place control measures to ensure the knotweed is not spread to other areas of the site or beyond site boundaries
  • To establish a system of monitoring and recording knotweed re-growth
  • To determine the success (or otherwise) of the knotweed treatment programme
  • To provide a clear written record of the knotweed evaluation and treatment, in the event of any future dispute

By giving the knotweed proper consideration and providing education to all site personnel, a KMP can establish a plan of action right at the beginning of the project and ensure each contractor employed on the scheme will understand their responsibilities in this regard. The instigation of good hygiene procedures will ensure subsequent site works will not affect the knotweed treatment schedule or inadvertently spread the knotweed to other areas, where it could be responsible for delays to the development process and cost money due to stoppages and additional treatment.

It is usual practice for a copy to be retained on site throughout the development works and for a second copy to be retained by the designated clerk of works (if different from the Site Manager). Both copies will need to be continually updated as the project progresses. On completion, the KMP can be retained as part of the CDM file. It is recommended that a copy be given to the future site owner for their records.

The Knotweed Company can draw up a KMP for your site, provide ‘Toolbox Talks’ to induct Site Managers and site personnel in knotweed identification and best practice, review site hygiene procedures to ensure knotweed material is not spread around or off site and, if required, act as the designated clerk of works to administer the Plan throughout the development project.