At SE Knotweed, Japanese knotweed removal costs from around £1,200 for a herbicide programme to £12,000 for full excavation on a large site. The method, the size of the stand and site access drive the figure, which we fix at survey.
Removal costs from around £1,200 for a herbicide programme to £12,000 for full excavation, and we give a fixed figure at survey once the stand is measured.
Japanese knotweed removal costs from around £1,200 for a herbicide programme on a small stand to £12,000 for full excavation on a large or awkward site. The figure is driven by the method, the size of the stand, machinery access and whether soil leaves the plot.
At SE Knotweed, we measure the stand at survey and give a fixed price, so please treat these as indicative until the site is seen.
Herbicide treatment costs from around £1,200 to £3,500 across the programme, on-site relocation £3,000 to £8,000, and full excavation £4,000 to £12,000. A root-barrier membrane sits in the middle depending on the run length.
The cost by method page breaks each down, and the schedule below sets speed against relative cost so you can weigh them.
Stand size changes the price because it sets the herbicide visits, the volume of soil to excavate and the disposal cost. A single clump behind a shed is a different job from a stand running the length of a boundary.
The cost by size page gives indicative figures for small, medium and large stands, and we confirm yours at survey.
Contaminated soil is expensive to remove because knotweed soil is controlled waste under the Environmental Protection Act 1990, so it must be carried by a registered waste carrier, tracked on a waste transfer note and taken to a licensed facility that charges a gate fee.
That chain, plus the machinery and labour to dig, is why excavation costs more than a herbicide programme that leaves the soil in place.
Removal is sometimes covered by buildings insurance, though many policies exclude knotweed, so it is worth checking the wording. Where a neighbour is the source, some or all of the cost may be recoverable, which the encroachment claims page explains.
Either way, we set out the figure clearly and can provide the documentation an insurer or solicitor asks for.
An accurate quote comes from a survey, because the price turns on the measured stand, the method and site access rather than a photograph. We inspect the site, confirm the RICS category and issue a fixed figure with the management plan.
Book a survey and we will give you a costed plan you can act on, with the fee often credited against the treatment.
| Method | Speed | Relative cost | Best for | Soil / waste | Guarantee |
|---|---|---|---|---|---|
| Herbicide treatment | 3 to 5 seasons | Lowest | No sale deadline, soil can stay in place | Minimal | Insurance-backed |
| Excavation and disposal | A few days | Highest | Fast clearance and development plots | Soil removed under licence | Insurance-backed |
| On-site relocation (cell burial) | 1 to 2 weeks | Medium to high | Larger sites keeping soil on the plot | Buried on site to a cell | Insurance-backed |
| Root-barrier membrane | Days | Medium | Containing spread at a boundary | Minimal | Situational |
| Combination treatment | Varies | Medium | Mixed or access-restricted sites | Varies | Insurance-backed |
Tell us the address and what a surveyor flagged. We confirm the plant, record the RICS category and set out the figures.