Since RICS published its new guidance note for surveyors dealing with Japanese knotweed at the end of January, there’s been a great deal of confusion about what it actually means for homeowners and buyers.

This is partly down to some serious misreporting in the press, with a number of national newspapers stating that the new rules mean knotweed will no longer be considered at all by surveyors unless it’s causing physical damage to property. The guidance has also been widely misinterpreted by property professionals, including surveyors and conveyancers, across social media.

So, what are the main rule changes and what do they mean?

• The ‘7 metre rule’ has been scrapped in favour of a more nuanced approach, allowing surveyors to use their professional judgement to determine the potential impact of knotweed. This doesn’t mean knotweed no longer poses any threat to property transactions! It just means the focus is no longer just on the risk to buildings, but other factors too such as the often-serious impact on use of the garden, or ‘amenity value’.

• The new guidance recognises the problems that can arise from encroachment of knotweed from adjoining land. Surveyors are required to flag infestations on adjoining property within 3 metres of a boundary, recognising that cases of encroachment from a neighbour’s garden are often more problematic and costly than if the plant was on the seller’s own property, because legal redress comes into play. Buyers need to be aware if they’re about to walk into that situation.

• There’s an increased focus on ‘control’ of knotweed over ‘eradication’, in other words, herbicide treatment over excavation/removal. This means that in many cases, RICS believes knotweed can be effectively controlled with herbicide and a full excavation may not be necessary. Environet still firmly believes that in most situations eradication should be the goal, since herbicide treatments can induce the plant into dormancy meaning it can regrow in the future – particularly if the ground is disturbed. Removal of knotweed is the best way to preserve property values.

Our myth buster below might help…

MYTH: Surveyors no longer need to flag Japanese knotweed unless it’s causing visible damage to property.

FACT: Surveyors are required to impose a mortgage retention, i.e. recommend to a mortgage lender that they should not lend on the property without a specialist Japanese Knotweed Management Plan in place, if knotweed is causing visible damage AND if it’s likely to prevent or restrict use of the garden. If knotweed is present but not causing damage to buildings or amenity space, the surveyor is not required to impose a mortgage restriction, but the infestation will still be flagged in their report and can still impact their valuation.

MYTH: If knotweed isn’t posing a direct threat to my house, I can now sell it for the full value.

FACT: This is unlikely, since surveyors are still required to flag the presence of knotweed in their report and the seller will still be required to disclose its presence when they come to sell. This means buyers will be made aware of an infestation and are likely to renegotiate the price to reflect the cost of treatment at the very least. They may also walk away from the purchase, meaning the seller is forced to lower the asking price to secure a sale. Both of these factors mean it’s unlikely a house with knotweed will sell for the full value, even if the infestation falls into categories C or D meaning the surveyor is not required to impose a mortgage retention.

MYTH: Japanese knotweed will no longer be considered in house valuations from March 2022.

FACT: RICS have not scrapped their knotweed rules for surveyors. In fact, they’ve strengthened them, upgrading from an Information Paper to a more authoritative Guidance Note, which continues to recognise the very real risk knotweed poses to homeowners and lenders. Four categories (A to D) are in place reflecting the level of risk to help surveyors assess the impact of the infestation and its effect on the property’s value. It’s a willing buyer and willing seller, with full knowledge of the extent of the problem, including its impact on amenity value and liability for spread across boundaries, that determines what a property is worth. The new guidance is unlikely to change the opinion of an informed buyer who is aware of the very real risks posed by the plant.

MYTH: Japanese knotweed isn’t a problem anymore, so I don’t need to deal with it.

FACT: You are still legally required to declare if your property is “affected” by knotweed when you sell and complete the TA6 form, which is part of the conveyancing process. Surveyors are still required to inform a buyer of the presence of knotweed in their report if it’s discovered during a survey. If the infestation falls into the first two categories (A and B) they are also required to impose a mortgage restriction meaning a professional management plan must be in place with an insurance-backed guarantee before a lender will provide a mortgage. Dealing with a knotweed infestation gives you the best chance of selling your home at its full value and protects you from the risk of legal action if the plant is allowed to spread to a neighbouring property.

You can read the full RICS Guidance Note here or view Environet MD Nic Seal’s response to its publication here.