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  • Writer's pictureJonathan Milner MRICS

The impact of climate change on the growing seasons of Japanese Knotweed

...and how surveyors need to respond

by Jonathan Milner, MRICS – Technical & Development Surveyor at Home Surveying.

Jonathan is a member of the RICS Governing Council for Residential Property, and a candidate in the 2023 RICS Governing Council Elections for the Residential Property Group seat.

In both of my current roles – at Home Surveying and on the RICS Governing Council – I'm always looking for ways to improve the quality of our surveys and keep up with the latest developments in the field. One of the biggest and potentially most costly challenges we’ve been looking at over the last 12 months is whether climate change is having an affect on the growing seasons of Japanese knotweed and other invasive plants, and the implications this has for surveyors.

In the past, surveyors could use the winter season as part of a defence if Japanese knotweed was not identified during a survey. Put simply, this was because the plant would die back during the winter, making it difficult to spot. But the changing climate means that Japanese knotweed may no longer be dying back as much as it used to, which means that surveyors who fail to identify Japanese knotweed during a winter survey may no longer be able to use the season as a defence if the plant is later found to be present.

At Home Surveying, we are aware of these changes and are working to respond to them. We recognize that historic training may no longer be relevant, and we are taking steps to ensure that our surveyors are more conscious of the potential presence of Japanese knotweed all year round. This includes providing ongoing training and support to our surveyors, as well as investing in the latest detection methods to help us identify the plant more accurately.

The wider industry are also working to gather evidence on what the changing growing seasons mean for surveyors and the impact on how Inspection standards need to evolve as the climate does.

While that work is ongoing, however, it is absolutely vital that all surveyors consider the presence of Japanese Knotweed when attending a property, regardless of the time of year. That has been a core element of the CPD sessions we have conducted with the Home Surveying team throughout the winter, and will be emphasised again when the ‘traditional’ growing season comes to a close later in the year. We would rather be proactive than wait on case law to decide changes to our inspection protocols and take a common sense approach to an evolving threat.

A change in the growing seasons for this invasive and potentially very costly plant is not a unique challenge to the industry, but it is an example of how important it is for surveyors to be agile in their approach, and for a continued focus on training and development to be aware of changes in the environment.

As an organisation, at Home Surveying we are committed to staying up-to-date with the latest developments in the field and ensuring that our surveyors are equipped with the knowledge and tools they need to identify Japanese knotweed all year round. By doing so, we can help to protect our clients from the financial risks associated with this invasive plant and ensure that they can make informed decisions when it comes to buying or selling property.


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