Ben Lindley, Company Director at Japanese Knotweed Ltd.
Last reviewed on .
Japanese knotweed is one of the most invasive and difficult-to-eradicate plants. Effective removal requires persistence and adherence to legal and environmental guidelines. At Japanese Knotweed Ltd we offer a variety of control and eradication methods.
Here are the main methods for getting rid of knotweed:
1. Chemical control (Herbicide use)
The most effective and widely recommended method is the use of glyphosate-based herbicides. The herbicide is applied as part of a planned programme of treatments in early summer and early autumn as the plant is drawing nutrients into its roots, making the treatment more effective. Multiple applications are necessary, typically 3, 5 or10 years. Knotweed may regrow less vigorously after the first treatment, requiring follow-up applications. Japanese Knotweed Ltd is BASIS accredited meaning we only use BASIS approved herbicides, and if the infestation is near water or protected sites, we obtain appropriate licenses.
2. Excavation
Excavation involves removing all contaminated soil and rhizomes, which is the only way to guarantee complete removal for a clean site. However, this generates controlled waste that must be disposed of at licensed facilities. Japanese Knotweed Ltd is licensed to handle and dispose of all knotweed waste. It’s important to note that even tiny fragments (as little as 0.5g) can regrow, so meticulous removal and disposal are critical.
3. Burial (on-site)
Knotweed material can be buried on-site under strict conditions: at least 5 metres deep (or 2 metres if using a geotextile membrane), with the Environment Agency notified at least one month in advance. Japanese Knotweed Ltd will always provide advice to clients who may prefer this option.
Legal and Environmental Considerations
You may also be at risk of being prosecuted if found guilty of disposing Japanese knotweed in the wild, binning or composting it as knotweed is deemed as ‘controlled’ noxious waste and therefore has legalities around its disposal. as such contaminated soil or plant material must not be removed off-site without proper licensing. Read all you need to know about Japanese knotweed and the law HERE.
Key Points to Remember
- Persistence is essential: Eradication typically takes several years.
- Do not compost or move knotweed waste: It can regrow from tiny fragments.
- Professional help is strongly advised especially for large or environmentally sensitive sites.
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Knotweed is extremely resilient: Its rhizomes can survive dormant for years, so treatment and monitoring must be persistent.
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Disposal of knotweed and treated soil must comply with environmental regulations: Failure to do so can lead to legal implications and fines.
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DIY removal is not recommended: Treatments should only be done if you have the appropriate skills, qualifications, licenses and business accreditations, and follow safety and legal guidelines.
| Method | Description | Pros | Cons | Notes |
|---|---|---|---|---|
| Professional Treatment | It’s always advisable to hire specialists for herbicide application or excavation and disposal | Effective, insured, legal disposal | Can be costly depending on the site and infestation size | Recommended for full eradication, ideal for change of land use or commercial development |
| Chemical Treatment | A programme of herbicide applications repeatedly over several years | Targets roots, relatively easy to apply by qualified and trained technicians | Requires multiple treatments and safety precautions | Needs persistence and proper timing of applications |
| Excavation | All parts of the plant, including rhizomes are dug out and removed or buried onsite | Immediate removal of root system | Must comply with controlled waste laws | Should only be carried out by a licensed contractor |
To summarise:
The best way to remove Japanese knotweed involves a combination of professional treatment and careful management due to its invasive nature and ability to regenerate from small root fragments. For most situations, chemical control with glyphosate, applied correctly and repeatedly, is the most practical approach for homeowners, local authorities, property management or businesses. Many commercial or construction industries will opt for complete removal if the land is deemed for development.
Professional removal is always recommended. Get in touch for more information on our treatment or removal services or to get a quote.