Japanese Knotweed: Gardening expert on the 'dos and don'ts' of 'gardeners worst enemy'

But how do you know whether you have Japanese Knotweed in your garden and how do you go about getting rid of it? Gardening expert Chris Bonnett from GardeningExpress.co.uk has given us his do’s and don’ts if you find it in your garden.

Japanese Knotweed is a gardener’s worst enemy. This invasive plant can get everywhere. Its root system and rapid growth can damage concrete foundations, buildings, roads and paving as well as push out native plant species.

The first step is knowing what it looks like. New red shoots which resemble asparagus spears start to appear in spring. The leaves are normally rolled up and dark green or red but as they begin to spread, become a vibrant green, heart shape with a point at the tip.

In late summer / early autumn, clusters of white / cream flowers appear. These look lovely but are not as harmless as they seem.

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Stems are bamboo-like and can grow up to three metres tall but it’s the roots or rhizome that you need to look out for. These can grow to depths of two metres and can extend up to seven metres horizontally from the plant. As little as 0.7g of rhizome is enough for a new plant to grow.

So if you find the dreaded plant in your garden, what should you do?


  • Do take action as soon as you identify Japanese knotweed. The more it establishes itself, the more damage it will cause and the harder it will become to remove.
  • Do wash thoroughly any clothes or shoes that come into contact with the weed. This will reduce the risk of contamination.
  • Do check any previously contaminated areas for regrowth.
  • Do stop any Japanese Knotweed on your land from spreading off the property. You do not have to legally remove the plant but if it’s causing a nuisance, can be prosecuted for causing it to spread into the wild.

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source: express.co.uk