Will burning kill Japanese knotweed?
By Jennifer Holmes

Will burning kill Japanese knotweed?

Is burning japanese knotweed effective?

Knotweed is an extremely resilient species – it can survive extreme temperatures both hot and cold. The only benefit from burning the stems, leaves and crown is there’s less material to cart away after excavation and removal – which will be required to completely get rid of it. The truth is burning will not kill knotweed.

What happens when you burn Japanese knotweed?

Fire reduces most things to dust, so surely putting a match to it will kill it? The truth is knotweed will set alight, especially when its stems turn brittle in the winter, but whilst setting Japanese knotweed on fire may initially appear to be killing it off, in truth it’s only the tip of the iceburg (so to speak). The flames will only be burning off off the visible above ground growth and what lies underground will remain viable. Because the rhizome (root system) lies deep underground (up to 1.5 metres) and grows laterally up to 3 metres any burning will only affect localised plant material, leaving the rhizomes free to regrow. In fact burning in itself may annoyingly stimulate the rhizome to grow more rapidly.

Should you burn Japanese knotweed?

The answer is ‘no’ – we would never recommend burning knotweed as a method of control. For reasons stated above, burning does not eradicate all of the knotweed – it will merely leave some black charred holes in the landscape.

Is it illegal to burn Japanese knotweed?

There are legalities and regulations around burning (or disposing of) any plant material that is termed as ‘noxious’. It requires a waste management license, or in some parts of the UK ‘exemption’.

The regulations state that the activity does not:

  • endanger human health or cause pollution to water, air or soil
  • constitute a risk to plants or animals
  • cause a nuisance, eg in terms of noise or odour
  • adversely affect the countryside or places of special interest.

What gets rid of Japanese knotweed permanently?

The only real permanent solution if you want to completely get rid of knotweed is excavation. This can effectively be carried out on both residential and commercial properties, leaving the land problem free. Speak to us about getting rid of Japanese knotweed the professional way – don’t burn it!