Japanese knotweed in Carmarthenshire: Where it is growing

Kidwelly has the highest recorded occurrences in a 4km radius with over 110.

This figure is significantly greater than other towns in the area such as:

• Camarthen - 60
• Llandovery - 46
• Newcastle Emlyn - 21
• Llandeilo - 19
• St Clears - 19
• Laugharne - 8

Meanwhile, an area to the east of Pontarddulais, just outside Carmarthenshire has had over 300 occurrences.

Heat map of Japanese Knotweed in Carmarthenshire from Environet (Image: Environet)

Japanese Knotweed is an invasive plant that came to the UK during Victorian times and is viewed as a pest species which causes damage to its surroundings.

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

At the time of writing, there are around 55,500 known occurrences of Japanese Knotweed in the UK.

Many believe European adventurer Philipp Franz von Siebold transferred Japanese Knotweed to Europe from a Japanese volcano.

In 1850, a sample from the plant was given to the Royal Botanic Gardens in Kew, London.

Gardeners initially favoured knotweed because it had a similar appearance to Bamboo and was easy to grow.

So, it is perceived the weed was spread all over the UK, helped by water and rail networks.

How to spot Japanese knotweed

Knotweed hibernates over winter but in March or April it begins to grow, with red or purple spear-like shoots emerging from the ground which quickly grow into lush green shrubs with pink-flecked stems and bamboo-like canes.

The plant can cause major problems for homeowners if unchecked as knotweed has the ability to grow in cavity walls, drains, pathways, tarmac driveways and cracks in concrete.

The roots of Japanese Knotweed can grow as deep as three metres and spread up to seven metres horizontally.

Knotweed is unlikely to cause irreparable damage to property due to regulation, yet the plant can cause legal disputes between neighbours and affect a property’s value by around five percent.

Why is Japanese knotweed so notorious?

Japanese Knotweed is widely regarded as one of the most invasive plants which is known to cause damage to properties.

Knotweed is extremely hard to get rid of because its root systems can grow three metres deep and if a few centimetres of root is left behind, the plant will regrow.

However, some believe Japanese knotweed has the same effect as shrubs growing next to a premises and is not hazardous.

What to do if you have Japanese knotweed

Firstly, to get rid of knotweed, you should invest in a professional Japanese Knotweed survey and discover the extent of the infestation. This will tell you where the plant derived from and the best solution to remove it.

Then, professional treatment should be administered, which consists of herbicide for excavation of the infestation.

To report further sightings of Japanese Knotweed in your area, use the heat map feature on Environet.