Japanese knotweed might look harmless but it can grow up to two centimetres a day, smash through concrete and can even survive burning.

Experts are expecting a surge of the invasive plant in south-east London and north Kent after a particularly warm and wet winter.

The weed, which has bamboo-like stems, can grow up to a metre a month and can shoot up to seven foot in total.

It spreads through stem fragments, not seeds, so cutting the stems back can make the problem worse as a 10cm piece of stem can create a new plant in just 10 days.

According to the environment agency it can take up to three years to eliminate Japanese knotwood by spraying it with chemicals.



It can damage houses by spreading its roots under buildings and house sales have fallen through after the plant was found on the property.

Chief executive of the Property Care Association (PCA) trade body Steve Hodgson told News Shopper: "The first thing to say is don't be tempted to strim it, dig it up or mess about with it.

"The chances are it will make the problem far worse.

"The way to handle it is to get somebody who understands what it is, where it is and can come back with a responsible, cost-effective strategy to get rid of it."

It is not illegal to grow the plant on your own property but it is an offence to cause it to grow in the wild.

In 2013 Kenneth McRae, from the West Midlands, was “driven mad” over fears the plant could destroy his home and killed his wife before committing suicide.

For more information about what to do if you spot Japanese Knotweed on your property visit the environment agency website.