⟶ Field notes
The knotweed
journal.
Identification, treatment, the law, costs, and the occasional war story from a job site. Written by the surveyors who actually do the work.
61 articles
Removing buddleia from listed buildings without losing the consent
Listed building consent considerations when treating self-seeded buddleia on chimneys, parapets and stonework — what works, what gets refused.
5 August 2026 · 5 min read
Read articleSpecies
Cotoneaster on limestone grassland: a quiet ecological emergency
Wall cotoneaster and small-leaved cotoneaster are on Schedule 9 — and they are smothering some of the rarest grassland habitats in Wales and the West.
3 August 2026 5 minSpecies
Parrot's feather in garden ponds: removal and disposal
Myriophyllum aquaticum was a popular pond oxygenator before its 2014 sale ban — here's how to remove it from a domestic pond without spreading it further.
24 July 2026 5 minSpecies
Buddleia on Victorian buildings and railway infrastructure: why it matters
The structural damage caused by self-seeded butterfly bush, and the proven remediation method for masonry, gutters and rail ballast.
20 July 2026 6 minSpecies
Floating pennywort on UK rivers and canals: the worst case we've seen
Hydrocotyle ranunculoides can double in volume every 5–7 days in warm weather — here's why catchment-scale response is the only option.
16 July 2026 6 minProperty & Law
Bamboo encroachment claims in 2026: where the case-law stands
The County Court has heard a steady run of bamboo nuisance cases since 2023 — here's how the damages and remediation orders are settling out.
11 July 2026 6 minCase Study
Restoring an SSSI woodland after rhododendron clearance: the five-year plan
What happens after the chainsaws stop — how a cleared woodland recovers, and where active intervention pays off.
8 July 2026 6 minSpecies
Three-cornered garlic: the pretty Schedule 9 plant in half the gardens in South Wales
Allium triquetrum is on Schedule 9 — and most of the people growing it in their gardens have no idea.
2 July 2026 4 minTreatment
Specifying a bamboo root barrier that actually works
HDPE gauge, depth, overlap and capping detail — the specification points that separate a working barrier from a wasted weekend.
1 July 2026 5 minProperty & Law
Knotweed on a new-build plot: NHBC warranty, developer liability and the buyer's options
What to do if knotweed appears in your new-build garden during the NHBC warranty period.
29 June 2026 5 minIdentification
Running vs clumping bamboo: how to tell which one you've planted
The single most important garden-centre question — Phyllostachys or Fargesia — and what to do if you got the wrong answer.
24 June 2026 5 minSpecies
Rhododendron and Phytophthora: why ponticum is killing larch and oak woodlands
The link between Rhododendron ponticum and Phytophthora ramorum, and why Forestry England and NRW prioritise its clearance.
22 June 2026 6 minProperty & Law
Invasive species due diligence for commercial property in 2026
Acquisitions, refinancing and portfolio audits — when to commission a Phase 1 invasive species survey and what it costs.
18 June 2026 6 minProperty & Law
Knotweed, Help to Buy and shared ownership: what changes when the lender isn't only the bank
Housing association staircasing, equity loan repayments, knotweed in the back garden — and how it all fits together.
15 June 2026 6 minSpecies
Himalayan Balsam: why pulling alone never works (and what does)
One missed riverbank fires 800 seeds per plant up to 7 metres downstream. Catchment thinking is the only way to win.
8 June 2026 5 minSpecies
Himalayan balsam: identification and the catchment approach to control
How to spot Impatiens glandulifera before the seed pods explode, and why hand-pulling beats herbicide on most riverbanks.
4 June 2026 5 minProperty & Law
The conveyancing solicitor's knotweed checklist (saved as a one-pager)
Eleven items every property solicitor should request when knotweed is disclosed or suspected on a sale.
1 June 2026 4 minProperty & Law
Building an extension or conservatory next to knotweed in 2026
Foundation design, root barriers, building control sign-off and warranty implications — what to know before the first trench is dug.
22 May 2026 6 minProperty & Law
Insurance-backed guarantees for knotweed treatment: what they cover, what they don't
GPI, Brunel, QANW — who underwrites IBGs in the UK, what they include, and how to read the small print.
19 May 2026 6 minTreatment
Treating giant hogweed on a riverbank: the three-season programme that works
Catchment-scale control of Heracleum mantegazzianum requires PPE, aquatic-approved herbicide, and patience — here's the method we use across South Wales catchments.
12 May 2026 6 minSpecies
Giant Hogweed: why the sap burns, and what to do if you find a stand
Phytophotodermatitis explained in plain English — and the steps to take before anyone gets hurt.
12 May 2026 6 minRegional
Cardiff Japanese knotweed hotspots: where it's spreading in 2026
Riverside corridors, post-industrial brownfield and Victorian rear gardens — the three Cardiff settings producing the most surveys in 2026.
2 May 2026 5 minProperty & Law
Neighbour knotweed disputes after Davies v Bridgend: what to do, in order
A practical step-by-step for homeowners whose neighbour has knotweed and won't act on it.
2 May 2026 7 minRegional
Birmingham's canals and the spread of knotweed across the West Midlands
Why the BCN canal network is the single biggest knotweed corridor in the Midlands — and what it means for nearby property.
26 April 2026 6 minIdentification
How to identify giant hogweed — and the four plants that fool everyone
The visual checks that separate Heracleum mantegazzianum from cow parsley, hogweed, hemlock and angelica — and what to do if you've touched it.
22 April 2026 6 minIdentification
How to identify Japanese knotweed (and the look-alikes that fool everyone)
The four reliable tells — stem, leaf, growth habit and flower — and the six common plants people mistake for it.
14 April 2026 6 minRegional
Knotweed in Bristol and the M4 east: a working surveyor's snapshot
From Avonmouth to Bath: where Bristol's knotweed clusters and what to know if you are buying or building.
9 April 2026 5 minProperty & Law
Planning conditions for invasive species on UK development sites in 2026
Local planning authorities now routinely attach invasive species conditions to consents — here's how to discharge them cleanly.
4 April 2026 6 minRegional
Knotweed in Newport: the brownfield premium nobody tells developers about
Llanwern, Pillgwenlly, the Usk corridor — the additional cost knotweed adds to almost every Newport development.
30 March 2026 5 minTreatment
Biosecurity on UK invasive species sites: the 2026 protocol
Tool sanitation, boot wash, vehicle protocol and waste segregation — the operational discipline that prevents one infested site from contaminating the next.
22 March 2026 6 minRegional
Swansea, the Tawe corridor and the legacy of post-industrial knotweed
Why Swansea has more knotweed per square mile than almost any other UK city, and what we do about it.
12 March 2026 6 minProperty & Law
The TA6 form in 2026: what the Law Society's wording change means for sellers
The updated TA6 Property Information Form asks sellers a more nuanced set of questions about Japanese knotweed — here is how to answer them correctly.
10 March 2026 5 minProperty & Law
Selling a house with knotweed: the TA6 form, explained without the panic
Disclosure is mandatory. With the right paperwork in place, the sale almost always goes through.
6 March 2026 5 minSeasonal
Spring 2026 invasive species checklist for UK property owners
A 10-minute walk around your boundary in March can save thousands later — here's what to look for, species by species.
2 March 2026 5 minRegulation
Invasive species law in 2026: what UK landowners need to know
A plain-English guide to the regulatory landscape facing UK property owners and developers in 2026 — Schedule 9, the IAS Order, EA/NRW notification thresholds and biosecurity duties.
26 February 2026 7 minRegional
Where knotweed grows in Cardiff: the postcodes we visit most
Roath, Grangetown, Llandaff North, Splott — a working surveyor's map of where Cardiff's knotweed actually lives.
22 February 2026 5 minTreatment
Herbicide programme or excavation? Choosing the right route
Three years and £2,500, or three days and £15,000? The honest trade-offs between the two main treatment routes.
17 February 2026 7 minProperty & Law
Japanese knotweed and UK mortgage lenders: the 2026 policy update
Where each of the major UK lenders stands on Japanese knotweed in 2026, including the new RICS 2022 guidance interpretations and category-based risk decisions.
4 February 2026 7 minTreatment
Stem injection vs foliar spray: which herbicide method actually works best?
Two professional techniques, two different jobs. The science, the costs, and which one we'd choose for your site.
4 February 2026 6 minTreatment
What knotweed removal actually costs in the UK in 2025
Real numbers — surveys, herbicide programmes, excavation, IBGs — and what makes a quote go up or down.
20 January 2026 6 minTreatment
What invasive species removal actually costs in the UK in 2026
Updated 2026 pricing for Japanese knotweed, giant hogweed, bamboo, rhododendron, balsam and buddleia — surveys, treatment programmes, excavation and IBGs.
12 January 2026 8 minProperty & Law
Knotweed and your mortgage in 2026: every major UK lender's current position
Halifax, Nationwide, Santander, Barclays, NatWest, HSBC, Principality, Lloyds and the rest — what each one will and won't lend on.
8 January 2026 8 minSpecies
American skunk cabbage: the yellow flag of a wet woodland in trouble
Lysichiton americanus — banned from sale since 2016, still spreading through Welsh and West Country wet woodland.
21 December 2025 5 minSeasonal
Why winter is the best time to commission a knotweed survey for 2026 treatment
Late winter is the quietest time in our diary — and the surveys we do now feed straight into a first treatment in April or May.
8 December 2025 4 minSpecies
Crassula helmsii in garden ponds: why it's banned, and how to get rid of it
New Zealand pygmyweed — sold for years as a pond oxygenator, now one of the most damaging aquatic invasives in the UK.
8 December 2025 5 minSpecies
Three-cornered garlic, montbretia and Spanish bluebell: the minor invasives that bother gardeners most
Not on Schedule 9, not catastrophic — but they take over and they are surprisingly hard to remove.
25 November 2025 5 minIdentification
Giant hogweed vs cow parsley vs hemlock: telling the umbellifers apart
Three white-flowered umbellifers — one is harmless, one is toxic, one will burn you. Here is how to know which is which.
12 November 2025 6 minSeasonal
Knotweed through the year: what it looks like in every season
A month-by-month visual guide so you can spot it in March as easily as in August.
10 November 2025 5 minRegulation
Environment Agency, NRW and Defra: who you have to notify and when
Notifications, permits and exemptions for knotweed work near watercourses, on common land, and on regulated sites.
31 October 2025 5 minIdentification
The pre-purchase knotweed survey: what your buyer's surveyor will look for
A walk-through of what a PCA-member surveyor checks during a 60-minute pre-purchase visit.
19 October 2025 5 minTreatment
Knotweed under decking and garden buildings: what we find when we lift the boards
Why the dark, undisturbed space under timber decking is the perfect knotweed nursery — and how to deal with it.
6 October 2025 5 minTreatment
Knotweed on the allotment: site-wide thinking, not plot-by-plot
Why allotment associations need a single coordinated treatment strategy — and what it looks like in practice.
22 September 2025 5 minCase Study
Case study: a Cardiff Victorian terrace with knotweed under the back wall
A pre-sale instruction, a four-week turnaround, and a buyer who never asked a second question.
22 September 2025 5 minSpecies
Rhododendron ponticum: clearing a woodland without making it worse
Why ornamental rhododendron is a Forestry Commission priority — and what a five-year clearance programme actually looks like.
15 September 2025 6 minRegulation
Knotweed and controlled waste: what the law actually requires
EPA 1990, Wildlife and Countryside Act, Hazardous Waste Regulations — what each one says about moving knotweed soil.
8 September 2025 6 minTreatment
Root barriers and knotweed: when they work, when they don't
HDPE membranes are not magic. The thickness, depth and detailing all matter — and most failures are detail failures.
25 August 2025 5 minTreatment
On-site bund burial of knotweed: when it works and when the regulator says no
A practical guide to engineered cell burial on development sites — the cheapest legal route when conditions allow.
12 August 2025 6 minSpecies
Buddleia on buildings: a small problem until it isn't
Why butterfly bush is a structural engineer's least favourite shrub, and how we treat it without making the masonry worse.
4 August 2025 5 minTreatment
Glyphosate concerns: should you worry, and are there alternatives?
An honest look at the science, the regulation, and what we use when glyphosate isn't the right tool.
22 July 2025 6 minSpecies
Running bamboo is the new knotweed — what owners and buyers need to know
Civil nuisance claims, root-barriers, and why surveyors are starting to flag Phyllostachys at pre-purchase inspection.
21 July 2025 7 minTreatment
DIY knotweed treatment: every reason it almost always fails
Garden centre glyphosate, hot water, salt, weed-killer fabric — what we see when homeowners have tried it themselves.
8 July 2025 5 min