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Japanese knotweed alongside a Gravesend hedge: the Schedule 9 and controlled waste rules before any soil moves

Japanese knotweed (Fallopia japonica) can turn up on any site, and it is more likely beside rivers, railways and former industrial land. When it appears next to a hedge, the question is never simply "how do I get rid of it." The question is: what does the law require before any soil moves?

What the law says

Two distinct legal instruments govern Japanese knotweed in England. They operate in parallel and neither excuses non-compliance with the other.

Schedule 9, Wildlife and Countryside Act 1981

Japanese knotweed is listed in Part II of Schedule 9 of the Wildlife and Countryside Act 1981. Under section 14(1) of that Act, it is a criminal offence to plant, or otherwise cause to grow in the wild, any plant listed in Part II of Schedule 9. The phrase "cause to grow in the wild" is the operative risk: it is not limited to deliberate planting. Disturbing knotweed rhizomes so that fragments travel off your land via surface-water runoff, soil movement or green-waste skips, and those fragments then regenerate on adjacent wild or riparian land, is the mechanism by which the offence is typically engaged in a domestic or commercial hedge-clearance context.

Offences under section 14 of the Act can lead to a fine and, in serious cases, imprisonment. In practice, prosecutions in domestic garden contexts are rare, but Environment Agency enforcement notices and civil actions are not. The civil liability picture is discussed further below.

Environmental Protection Act 1990: controlled waste

Japanese knotweed material (cut stems, rhizome fragments, and soil containing roots or rhizomes) is classified as controlled waste for the purposes of the Environmental Protection Act 1990. This has two direct consequences.

First, section 33 of the EPA 1990 makes it a criminal offence to deposit controlled waste on land, or to keep, treat or dispose of it, except pursuant to a waste management licence or environmental permit. "Depositing" includes placing knotweed material in a skip, burying it on site, or transferring it to a neighbour or a general green-waste collector without the right authorisation. Summary conviction: an unlimited fine. Conviction on indictment: up to 5 years' imprisonment and an unlimited fine.

Second, section 34 of the EPA 1990 imposes a statutory duty of care on any person who produces, carries, keeps, treats or disposes of controlled waste. If you produce knotweed waste by cutting or excavating it, you are obliged to take all reasonable steps to prevent its escape, to transfer it only to an authorised waste carrier, and to ensure it is accompanied by a written waste transfer note describing the material, its quantity and the parties involved. Confirm current transfer note requirements with the Environment Agency or the licensed waste carrier before disposal, as the administrative detail can change.

Civil liability: allowing spread to adjacent land

In the 2018 Court of Appeal decision Network Rail Infrastructure Ltd v Williams and Williams [2018] EWCA Civ 1514, the court held that allowing Japanese knotweed to encroach on a neighbouring property from your own land constitutes an actionable private nuisance, even where no physical structural damage to the neighbour's land or buildings has occurred. The interference with the neighbour's quiet enjoyment, including the effect on mortgage-ability and saleability, was held sufficient. That decision has been widely applied in county court proceedings in England. If hedge work disturbs knotweed rhizomes and plant material migrates to a neighbouring garden, you face the risk of a damages claim regardless of whether the spread was deliberate. The practical standard is simple: treat knotweed as if every fragment matters, because rhizome fragments as small as 0.7 grams can regenerate under UK growing conditions.

Identification: what to look for before starting hedge work

Japanese knotweed is distinctive but can be missed when dormant or when growing through a dense hedge base. The key features:

• Stems: hollow, bamboo-like, with distinct nodes, typically dark-spotted red-green in the growing season, drying to a pale cream or tan in winter. New spring shoots are reddish-purple and asparagus-shaped.
• Leaves: large (typically 100-120mm), shield-shaped or heart-shaped at the base, coming to an abrupt flat-cut point rather than tapering. Arranged in a zigzag pattern up the stem.
• Height: typically 1-3 metres during the growing season, dying back to ground level each winter but leaving the previous year's hollow tan canes standing.
• Rhizomes: underground root-like stems that can extend up to 7 metres sideways and 3 metres deep from visible growth, according to Environment Agency guidance. Orange or yellow inside if snapped. These are the primary spread mechanism and the reason disturbing the soil without care is the main legal risk.
• Flowers: small, cream-white, clustered in spikes, appearing in late summer (typically August to October).

If you are not confident in your identification, get a written identification report from a qualified surveyor or the Royal Horticultural Society (RHS) before touching anything. An incorrect assumption in either direction is costly: treating non-knotweed as knotweed wastes money; treating knotweed as ordinary waste creates legal liability.

Steps to take when knotweed is found alongside a hedge

1. Stop and assess before touching anything. The most common way knotweed spreads during hedge work is via excavator buckets, rotovators, or simply dragging cut material across the site. If knotweed is present, the machinery or method you planned for the hedge job may need to change. Once you stop and identify what you are dealing with, the rest of the process follows a defined sequence.
2. Confirm the identification and record it. Photograph the plant clearly (stems, leaves, any visible rhizome) and the location relative to the hedge. Note the approximate extent of the growth area. If there is any doubt, commission a formal identification report. This record matters both for the insurance position and for any subsequent disposal paperwork.
3. Check for a Tree Preservation Order or conservation area status on the hedge. If the hedge or any tree within it is subject to a TPO under the Town and Country Planning (Tree Preservation) (England) Regulations 2012, or sits in one of Gravesham's 23 conservation areas, you will need written consent or a section 211 notice before significant work even before the knotweed question arises. Both constraints run alongside the knotweed rules, neither one cancels the other.
4. Check for active nests before any cutting, pruning or clearance.

   Active nests in or near the knotweed or hedge growth?

   Section 1 of the Wildlife and Countryside Act 1981 makes it a criminal offence to intentionally damage or destroy an active bird's nest. This obligation applies regardless of whether you also have knotweed or a hedge to manage: the two wildlife-law duties run simultaneously. Japanese knotweed provides nesting cover and is frequently colonised by blackbirds, robins and wrens, particularly in the early growing season. The main nesting window is 1 March to 31 August, though some species extend into September. Before cutting or disturbing any knotweed growth near a hedge, visually check thoroughly for active nests. If one is found, stop and wait until the chicks have fledged before continuing.

5. Do not allow knotweed material to leave your land without a licensed waste carrier and a waste transfer note. Contact a licensed specialist waste contractor (not a general green-waste or garden clearance firm unless they hold the correct Environment Agency environmental permit for knotweed-contaminated material). Confirm their licence details and obtain a waste transfer note describing the material, the quantity and the licensed disposal site before any material is loaded. The Environment Agency's public register of environmental permits is the check to run; do not rely on a contractor's verbal assurance.
6. Treat any soil within the knotweed growth zone as potentially contaminated. Japanese knotweed rhizomes extend well beyond the visible plant. A general rule used in practice is to treat soil within a 7-metre radius of visible growth as potentially knotweed-contaminated where rhizome evidence is not ruled out. Soil excavated from this zone must be handled as controlled waste and disposed of at a licensed facility, not used as fill elsewhere on site or taken to an ordinary soil recycling centre.
7. Decide on a management approach and document it. The main approaches are: chemical treatment with a systemic herbicide (glyphosate-based products are the most widely used; several treatments over two to four growing seasons are usually required before professional monitoring can confirm eradication); physical excavation and licensed disposal (faster but more disruptive and generates more controlled waste); or excavation with specialist on-site bund treatment (used on larger sites, less common in domestic settings). For a hedge renovation or removal job where knotweed is a secondary discovery, a herbicide treatment programme managed by a trained contractor is usually the proportionate response before the main hedge work resumes. Document the programme and the contractor's credentials.

Why the Thames corridor makes Gravesend higher-risk

Japanese knotweed was introduced to the UK from Japan in the nineteenth century as an ornamental plant, and it spreads along river corridors and railway lines as rhizome fragments travel with water, soil and machinery.

In practice this means that any hedge job beside a river, a railway or former industrial land is higher-risk for knotweed discovery than a comparable job elsewhere. I check for knotweed before any hedge renovation job in those settings, not just when a customer flags it.

Mortgage implications and the RICS guidance position

The Royal Institution of Chartered Surveyors (RICS) guidance on Japanese knotweed and residential property (revised 2022) sets out a risk-based approach that depends largely on how close the knotweed is to buildings and boundaries. Where knotweed is within about 7 metres of a habitable building or a neighbouring boundary, a management plan from a specialist contractor, usually with an insurance-backed guarantee, is typically expected before a mortgage lender will lend.

This is relevant to hedge work because: if knotweed is found during hedge renovation or removal and the work disturbs it without a proper management plan in place, the property becomes harder to sell or remortgage until a specialist treatment programme is completed and documented. The time to get that programme under way is before the disturbance, not after the damage is done.

Sources: Wildlife and Countryside Act 1981, sections 14 and 21 and Schedule 9 Part II (legislation.gov.uk); Environmental Protection Act 1990, sections 33 and 34; Environmental Protection (Duty of Care) Regulations 1991; Natural Environment and Rural Communities Act 2006; Network Rail Infrastructure Ltd v Williams and Williams [2018] EWCA Civ 1514; Royal Institution of Chartered Surveyors, "Japanese Knotweed and Residential Property" information paper (2022 edition); Wildlife and Countryside Act 1981, section 1 (nesting season duty); Town and Country Planning (Tree Preservation) (England) Regulations 2012; Environment Agency, Japanese knotweed: managing an invasive weed (gov.uk guidance).