Japanese knotweed is known for damaging homes, pavements, and drains, and can spread up to seven metres horizontally.
Environet UK, an invasive plant specialist, has made an online map to identify areas where the plant is most prevalent.
Lydney tops the list with 22 infestations this year, followed by Blakeney with 21, Cheltenham with 20, Gloucester with 13, Lechlade with 12, and Stroud with 11.
In South Gloucestershire, Mangotsfield has 39 infestations, Kingswood has 26, Stoke Gifford has 20, and Almondsbury has 12.
Overall, Gloucestershire has a total of 628 verified knotweed sightings, equating to 0.52 incidences per square mile.
The map, which shows nearly 58,000 known occurrences across the UK, is updated with new sightings throughout the year, providing a comprehensive record of Japanese knotweed in the country.
A map has revealed the hotspots where Japanese knotweed can be found (Image: Environet)
Japanese knotweed was first introduced to the UK in the Victorian era as part of a plant specimen collection delivered to Kew Gardens.
Its invasive nature was not initially recognised, and it spread rapidly across the country.
The plant typically emerges in March or April and can grow up to 2.5 metres high by mid-summer.
It is identifiable by its bamboo-like canes and distinctive shield-shaped bright green leaves.
Mature plants bloom in August, producing clusters of creamy-white flowers.
All UK plants are female, so knotweed does not produce viable seeds.
Instead, it spreads through the movement of soil or gardening waste, or via rivers and streams when pieces of rhizome break off.
Environet director, Emily Grant, said: “By mapping verified sightings, we’re helping people understand the level of risk in their local area and encouraging early identification and treatment.
“Vigilance is the best way to protect your property from Japanese knotweed, making sure you tackle it as early as possible before it becomes well established.
“Public engagement is key in the fight against knotweed, and by reporting new sightings, homeowners can play an important role in controlling this invasive plant and protecting property values.”
(Image: Environet)
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