Japanese knotweed UK: what does it look like, how to get rid of it, damage it can cause and removal explained

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Christopher Clarke told the judge the knotweed ‘comes through the door when you open the door’

A millionaire whose £1.6 million house has been significantly devalued by Japanese knotweed has taken his neighbour to court.

Christopher Clarke and Louise Kaye are suing their neighbours Talha and Minha Abbasi for a sum of £250,000 over the knotweed which is on their neighbour’s land.

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The couple bought their home in December 2014 for £1,159,999 and have been unable to secure a mortgage or sell it.

Their neighbours, the Abbasi’s have admitted knowing the knotweed was on their land, but contest the damages, stating it was there before they purchased the property.

Japanese knotweed is an invasive species that can cause severe disruption if not treated, it can destroy buildings and cost a significant sum to eradicate.

Here’s everything you need to know about this destructive plant and how you can get rid of it.

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What is Japanese knotweed?

Japanese Knotweed is a plant that is classed as an invasive species in the UK.

Japanese knotweed growing on a wallJapanese knotweed growing on a wall
Japanese knotweed growing on a wall | Environet Uk

It has bamboo-like stems that are capable of growing eight inches in just one day.

It is incredibly destructive and its roots are known to damage buildings and their foundations.

It was brought to the UK by Victorians as a decorative garden plant and was used to line railway tracks.

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It has no natural enemies and the plant is notoriously hard to kill.

What does Japanese knotweed look like?

Japanese knotweed is an invasive, fast growing plant, with its canes able to grow 8 inches in just one day.

Japanese knotweed in full bloom on a wall. Photo: Environet UKJapanese knotweed in full bloom on a wall. Photo: Environet UK
Japanese knotweed in full bloom on a wall. Photo: Environet UK | Environet UK

Its roots are particularly destructive and can penetrate up to 2 metres deep and 7 metres across.

According to Japanese knotweed UK there are a few tell-tale signs that you have the plant growing in your garden.

Features of Japanese knotweed will depend on the season.

Key things to look out for with Japanese knotweed:


  • Red shoots will appear
  • Rolled up leaves which spread out
  • Canes, similar to bamboo shoots, will grow upwards, with green leaves


  • Green, shovel shaped leaves
  • Clusters of white flowers
  • Leaves grow in a zigzag pattern


  • Leaves will grow yellow and start to wilt


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  • Canes will turn brown

How much damage can it cause?

Japanese knotweed can cause serious damage to both homes and gardens.

It will grow through small cracks and can decimate building foundations, walls and patios.

The issue is taken very seriously by mortgage lenders, with many refusing to offer a mortgage for a home impacted by Japanese knotweed.

The plant can also devastate gardens as its invasive roots will strangle other plants.

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If you are planning on selling your home, you are legally required to state whether the weed is on your property.

How can you get rid of it?

Japanese knotweed usually takes three years to completely eradicate.

According to the UK government website you are not recommended to treat knotweed unless you have experience in this area.

It suggests that you reach out to a company who specialise in killing it.

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The most common method of getting rid of Japanese knotweed is spraying or injecting the roots with chemicals.

The knotweed will have to be resprayed as it can remain dormant in the soil.

After the knotweed is killed it’s important that it is disposed of correctly to prevent any other infestations.

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