Knotweed specialist or RICS surveyor?

A sale is ticking along, then a comment lands in an email: “Possible knotweed near the boundary - please confirm.” Suddenly it is not about paintwork or a few garden jobs. It is about whether your buyer’s lender will proceed, what your solicitor will advise, and how quickly you can produce evidence that stands up.

This is where the choice matters: knotweed specialist vs RICS surveyor. They are not interchangeable, and picking the wrong one can cost you weeks.

Knotweed specialist vs RICS surveyor: who is for what?

A RICS surveyor is trained to assess buildings and property condition and provide valuation advice. They are often the first professional to flag “suspected Japanese knotweed” because they are already on site for a HomeBuyer Report, Building Survey, or valuation inspection.

A knotweed specialist is there for one job - to identify invasive plants accurately, assess risk in context (including boundaries and neighbouring land), and set out an appropriate management plan with clear evidence. The outputs tend to be designed for conveyancing, lender queries, and longer-term risk control rather than general property condition.

If you only remember one thing, remember this: a RICS surveyor can raise the question, but a knotweed specialist is usually the one who answers it with the level of detail transactions require.

What a RICS surveyor will typically do (and not do)

Most surveyors take a cautious approach. If they see anything that resembles knotweed - or if access is limited so they cannot be sure - they will record it as suspected and recommend further investigation.

That caution is sensible. Surveyors are not invasive-plant contractors, and on many inspections they cannot lift covers, enter dense planting, or spend extended time mapping a boundary line. They also work within the scope of a property survey, not a botanical survey.

A RICS report can therefore be excellent at triggering action, but limited as “proof”. It may note likely presence, approximate location, and a recommendation such as “consult a specialist and obtain a management plan”. For a buyer or a lender, that recommendation can pause the process until specialist evidence is produced.

What a knotweed specialist survey is designed to deliver

A specialist survey is built around certainty and documentation. It focuses on identifying whether Japanese knotweed is present, where it sits in relation to key features (buildings, patios, drains, fences, neighbouring land), and what needs to happen next.

That usually means measured observations, mapped locations, and high-quality photographic evidence that can be shared with solicitors, buyers, and managing agents. Importantly, it also means stating what was inspected and what could not be accessed, so the report is transparent and defensible.

Where knotweed is confirmed, a specialist should set out a treatment approach appropriate for the site - not a generic “spray it” suggestion. The right plan accounts for proximity to structures, boundaries, and the realities of access over multiple growing seasons.

Why lenders and solicitors often push you towards a specialist

Mortgage lenders and conveyancers want risk controlled, not opinions traded back and forth.

If a RICS survey flags suspected knotweed, the buyer’s solicitor may ask for one or more of the following: confirmation of presence or absence, a site plan and photos, a management plan, and evidence of an assurance mechanism such as an insurance-backed guarantee. Not every transaction will need all of that, but the direction of travel is consistent - written, shareable evidence that reduces uncertainty.

A specialist report is also easier to use when the knotweed is near or beyond a boundary. This is common in London and the Home Counties, where gardens are tight, fences are close, and infestations can sit on neighbouring land while still affecting your sale.

The main trade-off: speed and certainty vs a broader property view

There are situations where the surveyor’s note is enough to move things forward - for example, when the plant is clearly not knotweed and the issue is closed quickly, or when the property is being bought cash with no lender involvement and the parties accept a higher level of uncertainty.

But in most mainstream transactions, the risk of delay comes from ambiguity. A RICS report that says “suspected” is doing its job, yet it often triggers a second step. A knotweed specialist survey is that second step, and it is designed to end the “suspected” phase.

The most efficient route is often sequential: the surveyor flags it, then the specialist confirms and documents it properly, then the treatment plan (if required) is agreed.

When you should choose a knotweed specialist first

If any of the following applies, it is usually faster to book a specialist survey immediately rather than wait for a general survey to create the question:

• You are selling and you already know knotweed has been present on or near the property.

• You are buying and you have seen suspect growth in the garden, especially near fences, sheds, patios, or shared access routes.

• A neighbour has mentioned knotweed, or there is visible die-back/canes suggesting previous growth.

• You need documentation quickly to keep a mortgage offer or conveyancing timeline on track.

A specialist survey at the start is often the difference between controlling the narrative and reacting to it under pressure.

What “good evidence” looks like in a property transaction

People worry about knotweed because of property value, structural risk, and saleability. The antidote is not reassurance in conversation - it is a report that can be forwarded without further explanation.

Good evidence usually includes clear identification, comprehensive photos, a mapped diagram showing the extent and proximity to key features, and measurements that make the situation unambiguous. It also includes practical next steps: whether treatment is required, what method will be used, how long it will take, and what guarantee is available.

This matters just as much when knotweed is not present. A robust “not found” outcome, properly documented, can remove doubt before it turns into a negotiation point.

Boundary lines and neighbouring land: where disputes start

A common stress point is when the plant appears to be “next door’s problem”. Unfortunately, conveyancing rarely cares whose fault it is. Buyers care whether there is a risk to the property they are buying and whether it is being managed.

A knotweed specialist is typically better placed to inspect fence lines, track likely rhizome spread risk in context, and document what can be seen from accessible areas. If access to neighbouring land is needed, a specialist can also advise how to approach that - and what can still be concluded based on what is visible.

If you are a landlord or a property manager, this documentation can be equally important for internal governance. It shows you acted promptly and took reasonable steps to manage an invasive plant issue.

Treatment plans and guarantees: where the specialist route becomes decisive

If knotweed is confirmed, the next question is not “can it be removed?” but “how will the risk be controlled in a way a buyer and lender accept?”

This is where structured treatment plans and insurance-backed guarantees tend to carry weight. A plan that runs across multiple growing seasons reflects the reality of managing knotweed properly, and a guarantee provides a clear assurance mechanism if the plant reappears.

For many property owners, the emotional relief comes from having the problem placed inside a formal framework: survey, written report, treatment, and a guarantee that can be handed over to the next owner.

The simplest decision rule

If your goal is a broad assessment of a property’s condition, you need a RICS surveyor. If your goal is fast, transaction-ready certainty about knotweed - with evidence, mapping, and a clear management route - you need a knotweed specialist.

And if a sale or purchase is already under way, it is usually cheaper to move decisively than to lose a month to back-and-forth emails.

For owners and buyers across London, Surrey, Kent, Essex, West Sussex, and Hampshire, this is exactly why a dedicated knotweed survey product exists. Japanese Knotweed Group Ltd provides on-site surveys with a detailed written report, mapping and extensive photographic evidence, with next-day paperwork and the option to move straight into a structured treatment plan with a 10-year insurance-backed guarantee - details at https://www.knotweedgroup.co.uk.

The most helpful thought to keep in mind is this: knotweed is stressful when it is vague. Once it is measured, mapped and placed into a plan, it becomes a managed property issue - and that is what lets buyers, lenders and owners breathe again.