You have a legal responsibility to control it

Japanese knotweed (Fallopia japonica) has the potential to damage buildings and structures as well as overpowering native species, and the peak growing season is here again.

This invasive plant thrives in early spring and in any type of soil, no matter how poor. It grows as much as 20 centimetres per day, and can reach a height of 1.5 metres by May and 3 metres by June.

Luckily, if an outbreak of Japanese Knotweed or other hybrid of knotweed establishes itself at your premises and your block of flats buildings insurance policy with Deacon can cover the costs to eradicate it and dispose of the waste.

The Japanese knotweed plant can regenerate from rhizome (a root found underground) fragments as small as 0.7 gram and can remain dormant in the soil for over four years.  Clearly, a professional approach to its eradication is vital if 100% success is to be guaranteed – and if you are to stay on the right side of the law.

Under the Wildlife and Countryside Act 1981, it is an offence to allow the plant to spread. All parts of the plant, and any soil contaminated with the rhizome, are classified as “controlled waste”, and you have a “duty of care” under the Environmental Protection Act 1990.

If you think you may have Japanese Knotweed affecting your property, it is vital that action is taken to eradicate it.

You can see the Environment Agency’s advice here.

How to recognise Japanese Knotweed?

  • It produces fleshy red tinged shoots when it first breaks through the ground
  • It has large, heart or spade-shaped green leaves
  • It has leaves arranged in a zig-zag pattern along the stem
  • It has a hollow stem, like bamboo
  • It can form dense clumps that can be several metres deep
  • It produces clusters of cream flowers towards the end of July
  • It dies back between September and November, leaving brown stems

Please refer to your flats insurance policy wording for full cover details.  As with all insurance policies, the policy is subject to limits, conditions and exclusions. For more information please contact us to discuss further, or request a full summary of the cover or the full policy terms and conditions.

Reviewed December 2021
First published April 2017

The sole purpose of this article is to provide guidance on the issues covered. This article is not intended to give legal advice, and, accordingly, it should not be relied upon. It should not be regarded as a comprehensive statement of the law and/or market practice in this area. We make no claims as to the completeness or accuracy of the information contained herein or in the links which were live at the date of publication. You should not act upon (or should refrain from acting upon) information in this publication without first seeking specific legal and/or specialist advice. Arthur J. Gallagher Insurance Brokers Limited (Gallagher) trading as Deacon accepts no liability for any inaccuracy, omission or mistake in this publication, nor will we be responsible for any loss which may be suffered as a result of any person relying on the information contained herein.