DESCRIBED by the Environment Agency as 'indisputably the UK’s most aggressive, destructive and invasive plant', Japanese knotweed has been identified in large quantities across Chester, Ellesmere Port, Frodsham and Neston.

The fearsome flora, whose roots are capable of growing through concrete, was first imported to the UK in the 19th century. Originally coveted for its beauty, durability and regenerative powers, the plant is now widely recognised as a pest which out-competes native species and damages building structures.

Able to grow up to 10cm a day during spring, the knotweed is characterised by its asparagus-like pink shoots, bright green shield shaped leaves and delicate creamy white flowers. It is extremely difficult to remove due to its hardy rhizomes, which can regenerate the plant from the smallest fragment of left over root.

Data gathered by invasive plant specialists Environet show that the destructive plants are found in the largest quantities in Chester, with between 41 and 48 occurrences registered within a four kilometre radius.

Chester and District Standard: The Environet Heatmap shows the concentration of Japanese knotweed across the borough.The Environet Heatmap shows the concentration of Japanese knotweed across the borough. (Image: Environet)

Areas on the outskirts of the city recorded much lower numbers, such as Guilden Sutton (17) and Huntington (15).

Elsewhere in Cheshire West, Frodsham displayed high numbers of Japanese knotweed, with 37 occurrences (within 4km), and Ellesmere Port and Neston show similar levels of the troublesome species with 11 and 12 occurrences respectively.

The resilient nature of the plant means that its notoriously difficult to remove. Environet say that attempting to dig up the extensive root systems can be 'backbreaking work' and it is almost impossible to fully treat the species without expert help. A combination of excavation and the use of herbicides is often recommended.

Allowing the species to spread from your land to neighbouring land or into the wild can also lead to prosecution.

Cheshire West and Chester Council asks residents to report the presence of invasive weed species on public land, providing the location, the species (if known) and the amount of weeds present, these details can be entered into their online form. If Japanese knotweed is discovered on private property it is the owner's responsibility.

Nic Seal, founder and managing director of Environet, said: "apanese knotweed tends to strike fear into the hearts of homeowners.

"But as long as they are aware of its presence and take action to remove it before it causes any serious damage or spreads to a neighbour’s property, there is no reason to panic.

"By publishing hotspots, we hope to raise awareness and encourage people in the area to be vigilant for signs of knotweed as the growing season takes off, so they can act quickly if needed.

"Anyone living near or moving to one of these hotspots would be wise to check their garden carefully, enter their postcode into the heatmap to find out how many known occurrences are nearby, and if in doubt seek expert help."

Hotspots for Japanese knotweed are available to view on the Environet Heatmap.