After homeowners won compensation when the infamous Japanese knotweed encroached on their gardens, we’ve looked into Japanese knotweed hotspots in the the counties of Pembrokeshire, Carmarthenshire and Ceredigion.

Homeowners in the Amman Valley with Japanese knotweed in their gardens recently won large compensation claims for damages totalling £42,500.

Four residents, who all live on Cwmamman Road, successfully sued Network Rail for Japanese Knotweed encroachment to their properties.

Environet has a Japanese knotweed distribution map which, through thermal imaging, identifies where the knotweed hotpots are located in the three counties.

Within the UK, Wales is a hotspot for Japanese knotweed. The south of the country is particularly affected as is the much of the mid-country coastline.

The worst affected area within the three counties is east of Fishguard with patches identified round the Dinas Cross, Cwm Gwaun and Newport areas.

Haverfordwest, Saundersfoot and Carmarthen are also registered as hotspots.

The plant is most commonly found near railway locations as it was traditionally used to support railway embankments and their surrounding.

If the plant has grown up to a metre onto a property or piece of land, owners could be entitled to make a claim.

Why is Japanese Knotweed so notorious?

Japanese knotweed has acquired a reputation as one of the most invasive plants which is known to cause damage to properties.

It is also notoriously difficult to kill – root systems can extend up to three metres deep and leaving even just a few centimetres of root behind will result in the plant quickly growing back.

Some argue that Japanese knotweed is no more dangerous to structures than having a tree or shrub growing next to a property.

What do you do if you find Japanese knotweed on your property?

A lot of hard work…

Some of the techniques that help with the removal of knotweed is spraying it with herbicides. Covering the affected area with non-translucent material can slow its progress.

The root system can also be dug out but this is labour intensive and disposing of the roots is difficult. Knotweed is classed as controlled waste in the UK, and disposal is regulated by law.

The UK Government website has tips on how to remove Japanese knotweed which can be found here.