NEW data shows that the destructive Japanese knotweed is highly present in Cardiff - but Penarth has somehow been spared.

Japanese knotweed is a plant that can be highly destructive, with the Environmental Protection Act (1990) classifying the weed as 'controlled waste'.

The weed can damage property, such as pavements and drains, and can spread as far as seven metres horizontally.

It is the most invasive plant in the UK and should be dealt with as soon as possible.

Data from invasive plant specialists Environet UK shows that there are currently around 55,000 occurence of the plant in the UK.

Penarth Times:

Penarth is mostly untouched by Japanese knotweed

A heat map of reported instances shows that South Wales is a hotbed of knotweed activity.

Cardiff is covered in red, showing there is a big problem with the weed in the capital, but Penarth remains a bizarre oasis with few instances reported.

In fact, there are 43 occurences of knotweed within four kilometres of Penarth, compared to around 300 cases in the worst-hit parts of Cardiff.

A spokesman for the Vale of Glamorgan council said: "The council takes a proactive approach to knotweed control on local authority land, working in partnership with a contractor that specialises in treating knotweed.

"More generally the Vale doesn’t have the large river systems that spread knotweed from areas where it is more prevalent and it can be more easily controlled."

Why is knotweed a problem?

It is unknown exactly why Penarth has few occurences of knotweed, but it may be down to residents identifying and dealing with the problem before it worstens as well as the lack of river systems.

The plant hibernates in winter but grows in spring.

Red or purple spear-like shoots break through the ground and can grow rapidly into shrubs with bamboo-esque stems.

The plant is extremely destructive and can reduce the value of a property by around five per cent.

Roots can grow three metres into the ground, making it difficult to deal with once it takes hold.

Once detected, a profesional survey should be booked to determine the extent of the infestation.

When the professionals are sure of exactly how much Japanese knotweed there is, herbicides are often used to get rid of it.

Residents in the Vale can dispose of any Japanese knotweed at the Merthyr Tydfil waste disposal site, provided 24 hours notice is given.