A new report has shown that Watford is among the worst hotspots for Japanese knotweed in the South East.

Environet UK has released a heatmap showing the areas of the UK with the most reports of the plant which can cause damage to properties.

Watford has seen 60 reported sightings within four kilometres, the second most in Hertfordshire after Elstree, which had 61.

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Watford Observer:

Rickmansworth had seen 28 within the same range, while St Albans saw just 19. Areas with denser populations are likely to have more reports, but Watford still sees many more than most comparable areas in the South East.

Japanese knotweed is an invasive plant that can grow through a home and impact the price of a property, usually by between 5 and 10%.

It typically costs between £2,500 and £15,000 to remove it from a home and there are legal pitfalls.The value hit was previously even higher, but as people now know more about the plant, panic has decreased.

Watford Observer:

Founder and managing director of Environet, Nic Seale, said: “Knotweed can cause damage to properties. Legally you are required to disclose the property as being affected. We get involved in a whole lot of legal cases where people get sued for misrepresentation.

"A lot of your readers may be tempted to have a go with a DIY method, which is fine, but they will need to disclose it was present. They might not kill all the roots and put it in a state of temporary dormancy and if you have declared it is not present and it comes back you could be sued.”

Watford Observer:

If you are not absolutely sure your property has never had a knotweed problem, it is not advised to declare you know it does not have one. Instead, it is best to say you do not know.

Knotweed spreads primarily through compromised soil being disturbed. This means that riverbeds and urban areas where a lot of development takes place are hotspots.

Watford Observer:

In some cases a relatively small amount of soil being imported and spread out for a large development can see an entire cricket pitch needing to be dug up.

Full heatmap availiable here

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