⟶ Frequently asked
Knotweed,
answered.
Scannable answers, with the detail surveyors, lenders and solicitors actually need. If yours isn't here, the phone is the fastest route to a real answer.
Talk to a surveyorQuick answer
Does Japanese knotweed stop a sale or a mortgage?
Not automatically. Under the RICS 2022 guidance, surveyors assess whether the stand damages a structure or restricts the usable garden, rather than applying a fixed 7-metre rule. Where a survey, treatment plan and eligible insurance-backed guarantee are in place, a transaction can usually proceed — but requirements vary, and the lender and its surveyor make the final decision.
Conditions: Guarantee eligibility depends on the survey findings, the treatment plan and the insurer's criteria; terms and exclusions are confirmed in writing.
Next step: Book a survey, or call 07582 869979 if a sale is already in progress.
Three reliable tells — and a free photo ID service if you're still unsure.
What to look for
- Hollow, bamboo-like stems with reddish-purple speckles
- Alternate heart or shovel-shaped leaves in a zig-zag along the stem
- Creamy-white tassel flowers in late summer
Common look-alikes
- Bindweed
- Russian vine
- Dogwood
- Lilac
- Ornamental bamboo
Send us a photo and we'll confirm it in writing — no fee.
Yes — the TA6 form requires it. Here's the clean way to do it.
The legal position
- TA6 sellers in England and Wales must disclose any knowledge of knotweed
- "I didn't know" is only defensible if it's actually true
- Misrepresentation claims after completion are increasingly common
How to sell cleanly
- Commission a professional survey
- Put a documented management plan in place
- Sell with an insurance-backed guarantee in hand
Almost always — provided you have a proper plan and IBG.
Lenders that accept a managed plan
- Halifax
- Nationwide
- Santander
- Barclays
- NatWest
- HSBC
- Principality
What they need to see
- Survey from a recognised contractor
- Written management plan
- 5 or 10-year insurance-backed guarantee
A handful of specialist or short-term lenders are stricter — we'll flag it up front if yours is one.
Three to five seasons for herbicide; days for excavation.
Herbicide programme
- Year 1: knock the plant back hard above ground
- Years 2–5: exhaust the rhizome network below
- Typical duration: 3–5 growing seasons
Excavation
- Days rather than years
- More disruptive
- More expensive up front
Fixed-fee after a site visit — no day-rates, no creeping extras.
Typical price guide
- Domestic herbicide programme (incl. IBG): £1,500–£4,500 + VAT
- Fixed-fee survey: from £295 + VAT
- Excavation projects: from £4,000 + VAT
Excavation scales with volume, access and disposal route. Every quote is fixed-fee after a site visit.
It exploits weakness — it doesn't crack sound foundations.
What it can damage
- Cracked drains
- Lifting tarmac
- Lightweight outbuildings
- Perished mortar
Why RICS surveyors flag it
Lenders care about value and saleability. Knotweed is mortgage-blocking where it impacts amenity space or causes damage to structures such as tarmac, sheds or fencelines — not just because of a fixed distance to the wall.
No — but spreading it or dumping waste is.
Key legislation
- Wildlife and Countryside Act 1981 — offence to plant or allow it to spread
- Environmental Protection Act 1990 — soil and plant material are controlled waste
- Disposal must go through a licensed route
This is why DIY clearance is rarely a good idea.
We strongly suggest not. Here's why.
The practical risks
- Rhizome can run 2–3 metres deep and several metres laterally
- A fragment the size of a fingernail will regrow
- Mishandled spoil becomes contaminated controlled waste
The legal risks
- EA / NRW duty of care on disposal
- Civil liability if any crosses a boundary
Treatment or licensed excavation are the two safe routes.
The full M4 corridor, West Midlands and Thames Valley.
Core coverage
- South Wales, Bristol, Bath
- Swindon, Reading, Slough
- Thames Valley and Greater London
- Birmingham and the West Midlands
- Gloucester, Cheltenham, Oxford
Larger projects further afield are quoted on request.
Knotweed is all we do.
What that means in practice
- Every survey signed off by qualified PA1/PA6 operatives
- Hundreds of UK sites under our belt
- Paperwork lenders and solicitors actually accept
Third-party cover that sits behind our workmanship warranty.
How it works
- Underwritten by an independent insurer
- If we cease trading, the underwriter funds further treatment
- Transfers the long-tail risk away from you
Our terms
- 5 or 10-year cover
- Fully transferable on sale
- Accepted by mainstream lenders
Yes — assignable for the remainder of the term, no extra cost.
What goes in the conveyancing pack
- The IBG assignment paperwork
- The original management plan
- The treatment record
Exactly what the buyer's lender wants to see.
Late June to September for herbicide; winter is great for everything else.
Why late summer for herbicide
The plant is in full leaf and actively translocating sugars — and therefore the chemical — down to the rhizome.
What we do off-season
- Surveys and quotes
- Excavation works
- Paperwork ready for the first treatment of the season
It's a statutory nuisance. Start with a paper trail.
Your legal position
- Anti-Social Behaviour, Crime and Policing Act 2014
- Community Protection Notices have been issued to negligent neighbours
- Civil claims for diminution in value are well-established
What to do first
- Written notification to the neighbour
- Photographic evidence with dates
- Independent survey report to back a formal complaint
Yes — single plots up to multi-hectare brownfield regeneration.
Who we work with
- Main contractors and housebuilders
- Local authorities
- Network Rail principal contractors
- Engineering and environmental consultancies
What's included as standard
- CPP and RAMS
- EA / NRW liaison
- On-site burial cells
- Screened soil reuse
- Licensed off-site disposal
No — applied correctly under PA1/PA6 certification.
How we apply it
- Targeted stem-injection
- Low-pressure foliar application
- Glyphosate-based, PA1/PA6 certified operatives
Re-entry
Safe to re-enter once the spray has dried — typically within an hour. Surrounding planting, lawns and pollinators are unaffected.
Not until the rhizome is verifiably dead or removed.
Why it matters
- Live rhizome will regrow through new foundations and slabs
- Building over invalidates most warranties
- Knotweed will exploit any service penetration
If the timeline is tight
We excavate, screen and either remove or bury under a root-barrier membrane to a validated depth — and document the lot.
5–10 working days typically. 72 hours for urgent.
Standard turnaround
- Survey visits: 5–10 working days across the M4 corridor and West Midlands
- Urgent pre-exchange or pre-planning: usually inside 72 hours
- Written report, plan and quote: within a week of the visit
Yes — Giant Hogweed, Himalayan Balsam, Rhododendron ponticum, Buddleia and running Bamboo.
Species we routinely manage
- Giant Hogweed (Heracleum mantegazzianum) — PPE-led cut, dig and stem-injection
- Himalayan Balsam (Impatiens glandulifera) — hand-pull and catchment co-ordination
- Rhododendron ponticum — mechanical clearance and stump treatment
- Buddleia (Buddleja davidii) — masonry-aware drill-and-fill
- Running Bamboo (Phyllostachys spp.) — root-barrier or full rhizome excavation
Surveys, written method statements and IBGs are available for each.
Yes — sap causes severe chemical burns that can flare for years.
What the sap does
- Phytophotodermatitis — UV-triggered blistering on contact skin
- Burns can recur seasonally for up to seven years
- Eye contact can cause temporary or permanent blindness
What to do if you spot it
- Do not strim or cut — that aerosolises the sap
- Keep children and pets well clear
- Send us a photo for confirmation, then we'll attend in full PPE
Running bamboo encroachment now sits alongside knotweed in civil nuisance claims.
The legal position
- Running Phyllostachys is not on Schedule 9, but it can support a private nuisance claim
- Surveyors and lenders increasingly flag it during pre-purchase inspections
- A documented boundary-dispute report carries weight with solicitors
Practical options
- Install an HDPE root-barrier along the boundary line
- Excavate the rhizome network on your side
- Stage a cut-and-treat programme on stems crossing the line
Late May to early July — before the seed pods explode.
Why timing matters
- Each plant fires 800+ seeds up to 7 metres when ripe
- Seeds remain viable for 18–24 months in the bank
- One missed season undoes two years of catchment work
How we run a programme
- Whole-catchment co-ordination upstream to downstream
- Hand-pull or strim before flowering
- Repeat sweep in late July to catch laggards
On masonry, gutters and lintels — yes. The roots wedge into mortar joints and lift coping stones.
Where it causes trouble
- Victorian and industrial brickwork with soft lime mortar
- Parapets, chimney stacks and behind cast-iron gutters
- Railway retaining walls and bridge abutments
Our approach
- Cut to base and drill-and-fill the stump with approved herbicide
- Repoint and patch masonry where roots have penetrated
- Re-inspect at 6 and 12 months to catch any regrowth
Rhododendron ponticum shades out woodland floor and harbours pathogens fatal to larch and oak.
The ecological damage
- Acidifies soil and blocks light to the woodland understorey
- Hosts Phytophthora ramorum — a Forestry Commission notifiable pathogen
- Listed under Schedule 9 of the Wildlife & Countryside Act 1981
Clearance programme
- Mechanical or hand clearance with biosecure tooling
- Stump treatment with approved herbicide
- Follow-up regrowth control over 3–5 seasons
Fixed-fee from £295 + VAT, with most BS-postcode visits inside the working week.
What you get for a Bristol survey
- On-site mapping of every visible stand across the BS postcode
- RICS-aligned written Knotweed Management Plan accepted by Bristol conveyancers
- Photographic record, marked plan and lender-ready paperwork inside 5 working days
Bristol is one of our busiest patches — daily crews cover BS1–BS16 alongside Bath, Newport and the wider South West.
Yes — crews based within the M42 ring cover Birmingham, Solihull, Wolverhampton and the wider Black Country.
What we deliver across Birmingham
- PCA-trained surveys across B1–B30 and the canal network
- Multi-season herbicide programmes or full excavation for brownfield sites
- Experience with HS2 corridor works and Birmingham City Council planning
Two centuries of industrial soil movement plus the UK's longest urban canal network make Birmingham one of the most knotweed-affected cities in England — most jobs get a same-week site visit.
Yes — Cardiff is our home patch. Most CF-postcode surveys turn around inside the working week.
Cardiff sale-ready paperwork
- RICS-aligned report ready for TA6 disclosure and the buyer's solicitor
- 10-year IBG underwritten for Principality, Halifax, Nationwide and the rest
- Same-week site visits across CF3, CF5, CF10, CF11, CF14, CF23 and CF24
Yes — daily routes from Reading and Slough through Heathrow into every London borough.
London-specific work
- Surveys across W, SW, NW, SE, E, N, EC and WC postcodes
- Experience with TfL, Network Rail and borough council protocols
- IBGs underwritten for every London-active high-street lender
London has the highest density of recorded knotweed sightings in the UK. Any property within a few hundred metres of the Thames, the Lea, the Wandle or a disused railway corridor should be screened before purchase.
Typically 3–5 working days across RG and SL postcodes, faster for pre-exchange.
Thames Valley turnaround
- Daily M4 routes between Reading, Maidenhead, Slough and West London
- Riparian specialists for Thames, Kennet and Jubilee River-side properties
- IBGs accepted by HSBC, Santander, Barclays and the rest of the panel
Yes — the Lower Swansea Valley is one of the densest knotweed patches in the UK. Crews based within 30 minutes of every SA postcode.
South West Wales work
- SA1–SA7 daily coverage across Swansea and Gower fringe villages
- Riparian programmes along the Tawe, Nedd, Tywi, Loughor and Gwendraeth
- Experience with Swansea Council and Carmarthenshire planning conditions
⟶ Decision table
Survey, treatment or excavation — which applies to you
There is no single right answer: the method depends on the plant, the access, the site constraints and your timescale. The comparison below is how we frame the choice on site. Scope, monitoring and any guarantee eligibility are confirmed in writing after a survey.
Survey & management plan
- When it suits
- Any sale, purchase, remortgage or dispute where a lender, surveyor or solicitor has asked what the plant is and what it affects.
- Expected duration
- Site visit 1–2 hours; written report typically within 5 working days.
- Limitations
- A survey identifies and quantifies the problem — it does not treat it. Underground extent is inferred from surface evidence, not excavation.
- Guarantee eligibility
- Not applicable; the survey is the document that establishes whether guarantee-backed work is available.
- Evidence produced
- Positive identification, mapped stand extent, proximity to structures and boundaries, photographs, risk rating and a costed plan.
Herbicide treatment programme
- When it suits
- Gardens, boundaries and amenity land where the stand can be left in place and the timescale is not driven by imminent development.
- Expected duration
- Typically 3–5 growing seasons of applications plus monitoring visits; visible dieback usually within 4–6 weeks of the first application.
- Limitations
- Rhizome remains in the ground during the programme. Not suitable close to open water without a permit, or where the ground has to be built on soon. Weather and access affect timing.
- Guarantee eligibility
- Usually eligible for an insurance-backed guarantee, subject to survey findings and insurer criteria; terms and exclusions are confirmed in writing.
- Evidence produced
- Management plan, dated treatment log, photographic record at each visit, annual monitoring reports and, where issued, the IBG certificate.
Herbicide plus root barrier or cell burial
- When it suits
- Sites where the stand sits against a boundary or a planned structure and the material can stay on site.
- Expected duration
- Installation days to a week; herbicide monitoring continues alongside, commonly 2–3 seasons.
- Limitations
- Needs space, machine access and (in England) compliance with Environment Agency burial requirements. Barriers control spread; they do not kill the plant.
- Guarantee eligibility
- Often eligible where the design and monitoring regime meet insurer requirements; confirmed case by case.
- Evidence produced
- Design drawing, burial or barrier record, waste and materials documentation, monitoring reports.
Excavation and removal off site
- When it suits
- Development, groundworks, or a sale that cannot wait — where the ground must be clean now.
- Expected duration
- Commonly 1–5 days on site depending on volume and access.
- Limitations
- Highest cost. Contaminated soil is controlled waste: registered carrier and permitted landfill required. Restricted access, services and neighbouring land can rule it out.
- Guarantee eligibility
- Typically eligible for a guarantee on verified clearance, subject to validation excavation and insurer criteria.
- Evidence produced
- Excavation method statement, waste transfer notes, tipping receipts, validation photographs and a completion report.
On-site screening or soil remediation
- When it suits
- Larger sites with volume to process and space to work, where landfill costs would be disproportionate.
- Expected duration
- Project-specific; typically 1–3 weeks plus a monitoring period.
- Limitations
- Needs plant, space and a competent supervising specialist. Not viable on small residential plots.
- Guarantee eligibility
- Eligibility depends on the remediation method and the monitoring period agreed at the outset.
- Evidence produced
- Remediation strategy, screening records, verification sampling, monitoring reports.
Monitor only
- When it suits
- Isolated stands with no structural or amenity impact, where an owner wants a documented position rather than works.
- Expected duration
- Annual inspection, ongoing.
- Limitations
- The plant continues to grow. Lenders and buyers rarely accept monitoring alone where the stand affects a structure or usable garden.
- Guarantee eligibility
- Not eligible — no treatment work is being carried out.
- Evidence produced
- Dated inspection reports and photographs showing change over time.
⟶ References
Sources and conditions
Statements about the law, waste handling, lender treatment and guarantees on this page are drawn from the sources below. Requirements change and individual lenders, insurers and local authorities apply their own criteria — check the current source before relying on any point.
- Japanese knotweed and residential property (Guidance Note, 2022)
RICS
The current valuation-and-management framework surveyors use. It replaced the 7-metre rule with an assessment of impact on amenity and on structures.
- Wildlife and Countryside Act 1981, section 14 and Schedule 9
legislation.gov.uk
Makes it an offence to plant or otherwise cause Japanese knotweed to grow in the wild. It is not an offence simply to have it on your land.
- Environmental Protection Act 1990, Part II — duty of care for controlled waste
legislation.gov.uk
Knotweed-contaminated soil and plant material is controlled waste; movement off site requires a registered carrier and a permitted receiving site.
- Anti-social Behaviour, Crime and Policing Act 2014, Part 4 — community protection notices
legislation.gov.uk
The route councils use where an owner's failure to control knotweed has a persistent detrimental effect on others' quality of life.
- Prevent Japanese knotweed from spreading
GOV.UK / Environment Agency
Official guidance on treatment, disposal and on-site burial requirements in England.
- Invasive non-native species guidance
Natural Resources Wales
The equivalent regulatory position for our Welsh sites, including waste and watercourse considerations.
- TA6 Property Information Form
The Law Society
The seller's disclosure question on Japanese knotweed, and the reason a management plan and guarantee are asked for at conveyancing.
- Invasive weed control — homeowner guidance
Property Care Association (PCA)
Industry code of practice for survey, management plans and insurance-backed guarantees.
Reviewed by
The survey team
PCA-certificated surveyors, Japanese Knotweed Elimination
PA1 / PA6A certificated surveyors who carry out the site visits, write the management plans and sign off the reports issued to lenders and solicitors.
Reviews the legal, lender, cost and treatment statements answered on this page.
What this page can't tell you
- Guidance is general. Identification, treatment choice and timescales can only be confirmed by a site visit — photographs alone are indicative.
- Lender and insurer requirements vary by institution and change over time. We state what is typically accepted, not what any named lender will accept on your case.
- Guarantee (IBG) eligibility depends on the plan chosen, the survey findings and the underwriter's acceptance. It is not automatic.
- Legal points summarise published law and guidance current at the review date. They are not legal advice.
Last reviewed · Questions on anything stated here: 07582 869979
⟶ Still not sure?
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