Japanese knotweed heat map and hotspots in Wiltshire in 2024

Japanese knotweed is a weed that spreads a great deal, particularly in the summer. 

After falling back to ground level over winter, the bamboo-like stems will sprout to heights upwards of seven feet; suppressing other plants' growth in the process. 

The knotweed, which is notoriously difficult to eradicate by hand or with chemicals, is not alien to Wiltshire, either, and begins to emerge around March and April.

Japanese knotweed can grow very quickly, and because of this rapacious growth, it has been known to cause damage to building structures and substructures by targeting weak points, such as cracks in masonry, and attempting to grow through them.

Now, Environet UK has revealed the knotweed hotspots across the county using data from its interactive online tracker. 

According to the tracker, there are 10 reported cases of knotweed within four kilometres of Swindon town centre. 

Knotweed occurrences in Swindon (Image: environetuk)

Across Wiltshire as a whole, there are 14 occurrences within the same distance in Chippenham, three in Royal Wootton Bassett, and five in Trowbridge.

Knotweed is much more prevalent in nearby Bath, with 83 occurrences within four kilometres, and 440 within four kilometres in the Bristol area. 

Nic Seal, founder of Environet, told the Eastern Daily Press: "Vigilance is the best way to protect your property from the risks posed by Japanese knotweed.

Knotweed occurrences in Wiltshire (Image: environetuk)

"Knotweed is easily identifiable during summer, but into the winter, the above-ground growth dies back and it becomes much harder to spot.

"It's also easier to conceal, so anyone viewing a property to buy should be extra careful.

"There are lots of horror stories out there but with professional help, knotweed can be successfully treated and a property's value can be largely restored."