Gardeners are being urged to inspect their gardens before September for Japanese knotweed, a destructive invasive plant that can slash property value and even block mortgage applications, according to the Royal Horticultural Society (RHS).
Why August Is the Best Time to Spot It
Japanese knotweed is at its most visible during late summer, when its tall, bamboo-like stems and clusters of creamy white flowers make established growth easier to identify. The RHS is calling on homeowners to check their gardens now, while the plant is still easy to spot.
The plant is notorious for its ability to regenerate from even tiny fragments of its underground rhizomes, which can lie dormant in the soil for years. Attempts to dig it out without expert guidance can spread fragments to new areas and potentially extend the infestation.
Legal and Financial Risks
Japanese knotweed is classified as an invasive non-native species and listed under Schedule 9 of the Wildlife and Countryside Act 1981. Its aggressive rhizomes form dense patches that choke out native plants and can push through cracks in paving, paths and other hard surfaces, causing costly structural damage.
The presence of Japanese knotweed on or near a property can reduce its value and make it difficult to sell or remortgage until the problem has been professionally treated and certified.
What Gardeners Should Do Next
The RHS stresses that correct identification is crucial, as several other plants have a similar appearance. If in doubt, gardeners should seek expert guidance before taking any action. The RHS advises against attempting to deal with the plant yourself and recommends contacting a professional company that specialises in Japanese knotweed removal.
Under no circumstances should the plant be disposed of in home compost, council green-waste collections or household waste bins, as this risks spreading it further and could carry legal implications, since Japanese knotweed is classified as controlled waste under UK law.
Gardeners are urged to inspect borders, boundaries and areas around sheds, fences and garden paths before September, as catching the problem early is the best way to prevent it from becoming more serious and more expensive.
