Knot what we thought? Japanese Knotweed update

As garden nuisances go, the subject of Japanese Knotweed has been a thorny subject for the property management industry for many years. In fact we’ve looked at this hardy intruder as the subject of our blogs in the past [https://www.forgeproperty.co.uk/blog/knot-wanted-green-impacts-on-property-prices/131]. It’s hit the headlines in recent years and Fallopia Japonica, to give it its proper name, has even been debated and addressed in Parliament, with regards to its negative and damaging impact on buildings. It was reported that if you’re buying a new property, it can cost anything from £2,500 upwards to get the plants removed and it also rings alarm bells with some lenders and various mortgage types too. Once it has taken root in your grounds, it’s your responsibility to get rid of and has been thought to decrease the value of a property by up to 20%.

Not weed?

But times and attitudes are changing. The RICS published last month a revised guidance notice, with regards to Japanese Knotweed and Residential Property, which is effective as of 23 March 2022. This new report includes new perspectives on the plant and its impact, both physical and financial, on properties. As with the RICS information paper published in 2012, an objective of this new guidance was to define ‘a much more nuanced and evidence-based’ approach to the plant’s impact. Also, a Defra report recommended that Japanese knotweed should be reframed as a ‘mitigatable environmental issue’, rather than solely as a ‘property or social issue’, calling for guidance that would ‘provide clarity for lenders and enhance coherence in lending policy’. For surveyors and valuers, it’s very important to have consistent guidance that can be used in multiple instances.

Collateral damage

The new guidance is designed both for valuers to report to lenders, but is also to support the decision-making for the range of onsite inspections and surveys carried out by RICS members. The new assessment process enables the valuer or surveyor to carry out a structured assessment that leads to ‘an objective definition of any knotweed infestation’ they may encounter. The big change here is a better understanding of the so-called ‘seven metre rule’. This concerned the overstated risk Japanese Knotweed posed via its proximity to permanent buildings. As a result of this, the RICS has stated that the plant poses little or no risk of structural damage to robust buildings, in good condition, with strong foundations and walls. This is as opposed to less sturdy structures with shallow or no foundations, such as lean-tos, conservatories, garages or walls. Any plant that is allowed to overtake a building, whatever state of repair it’s in, can cause a certain amount of damage – as anyone who has ever tried to clear guttering, facias or walls of a climbing plant such as ivy, can testify to that. It’s more about controlling the plant and mitigating against allowing it to incur damage. Knotweed is still a menace, but it’s the degree of menace it poses that has been reassessed.  

A controlled approach

There is now a recognition that the most appropriate objective when Japanese knotweed is encountered is to ensure an appropriate level of control, rather than to automatically aim for eradication. This new approach from RICS follows a report by the House of Commons Science and Technology Committee in 2019, where MPs described mortgage lenders’ approach to Japanese Knotweed as overly cautious. Some lenders wouldn’t entertain any lending on properties where Japanese Knotweed was mentioned in a mortgage application. This had become a little more flexible, with lenders looking at each instance individually, on a case-by-case basis. The impact of the new advice is yet to take effect, and it will be interesting to see how mortgage lenders re-evaluate property where Knotweed is a presence. Though Japanese Knotweed is still not a welcome and beloved plant for gardeners and homeowners, we’re pleased to report that it has been decided that it is ‘knot’ the huge problem it once was.