According to Environet, specialists in invasive plant removal for residential and commercial properties, only 27% of the photos submitted for analysis were correctly identified as Japanese knotweed. While this is an improvement from the 16% in 2023, a significant number of homeowners are still incorrectly identifying common plants as invasive species.
Commonly mistaken plants
Bindweed has emerged as the most frequently misidentified plant, accounting for 12% of incorrect submissions. It resembles Japanese knotweed with its rapid growth and bright green leaves. However, unlike knotweed, bindweed requires other structures for support and does not pose the same risks to property foundations. Other plants that are often confused with knotweed include dogwood, houttuynia, ivy, bamboo, dock, lilac, bramble, honeysuckle, and peony shoots in early spring.
The risks of misidentification
Japanese knotweed is a highly invasive plant that can cause structural damage and negatively impact property values. Misidentification can lead to unnecessary treatment costs and cause delays in sales, as mortgage lenders often require specialist assessments if the plant is suspected to be present.
In 2024, we reported on a case against Bridgend Council after Japanese knotweed encroached onto a property from council land. £4,900 was awarded for the diminution in value; however, on appeal, it was reversed because the knotweek had existed since 2013, and it was argued it had been present for years before the issue was raised, so the reduction in value couldn’t be avoided.
However, the case highlights the potential risks for reduced property prices, delays to property transactions, and fall-throughs.
Expert advice on identification
Emily Grant, director of Environet, emphasised the importance of ensuring accurate identification, saying that the best way to protect property is to be aware of the risks and ensure you can identify knotweed at different times of the year. If knotweed is present, it’s wise to act immediately to treat or remove it before it has the chance to spread further. With professional assistance, knotweed can be dealt with, and the value of a property can be largely restored.
For comprehensive guidance on identifying and managing Japanese knotweed, Propertymark offers assured advice on knotweed as well as a detailed consumer guide. These resources provide insights into the plant's appearance throughout the year, effective treatment methods, and the potential impact on property transactions.
Environet offers a free identification service where homeowners can send a photograph for expert analysis as well as advanced techniques and equipment to ensure thorough removal, minimising the risk of regrowth.
