Japanese Knotweed is the UK's most invasive non-native plant. Knotweed originally comes from the Far East. The Victorians  imported it as an ornamental plant.  It spreads rapidly  and easily via rhizomes and cut stems or crowns.

Under the Wildlife and Countryside Act 1981 as a plant that is not to be planted or otherwise introduced into the wild. The Environmental Protection Act 1990 also lists it as 'controlled waste' to be disposed of properly. You have a legal obligation not to allow it to spread if it occurs on your site.

How to kill knotweed

You can attempt to dig it up by the roots. You must remove every bit of root. Leave one little bit of root and it will come back with revenge!  The best method is to treat with a glyphosate-based herbicide, such as 'Roundup Pro Biactive'. This needs to be done between March and October when the plant is at it's peak growing time. It may take up to six weeks before you see the plant die back.

• Methods of controlling & removing weeds

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