Japanese knotweed (Fallopia japonica) affects an estimated 4-5% of UK properties, with remediation costs averaging £2,000-5,000 per residential site. Causing it to spread is an offence under the Wildlife and Countryside Act 1981, carrying fines up to £5,000 or two years' imprisonment. Major UK mortgage lenders refuse loans on properties with untreated knotweed within 7 metres of habitable space.
Key takeaways
- Japanese knotweed grows up to 20cm per day in spring, reaching 3 metres by midsummer
- Causing knotweed to spread is a criminal offence under the Wildlife and Countryside Act 1981
- Major mortgage lenders refuse loans on properties with untreated knotweed within 7 metres
- Professional herbicide treatment costs £2,000-5,000 and takes 3-5 years to complete
- Knotweed rhizomes extend up to 7 metres from visible growth and 3 metres deep
- All knotweed waste is classified as controlled waste requiring licensed disposal
japanese knotweed invasive plants knotweed identification property law weed control knotweed treatment
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