What is Japanese Knotweed?

Japanese Knotweed (Fallopia japonica) was introduced to the UK as an ornamental plant during the 1800s. It was brought originally to Kew Gardens and was admired for its abundant foliage which acted as a good backdrop to other plants. It is now commonly found along railway lines, riverbanks, roads and footpaths, in graveyards, on derelict sites or anywhere it has been dumped, dropped or deposited.

Japanese Knotweed is the most invasive plant in the UK today; it is difficult to kill and it spreads easily. It can grow by up to four inches a day and causes significant damage to man-made structures.

The roots system can spread up to seven metres in length and three metres depth from the visible plant and can survive in water for some time and still be viable when it comes into contact with soil.

It is an offence to fail to notify a potential purchaser of the existence of Japanese Knotweed on your land and mortgage lenders can legally refuse to give you a mortgage if Japanese Knotweed is recorded on or near a property. However many will still lend, if an appropriate contractually backed treatment plan is arranged between the buyer and the seller – this is where C&F can help!

japanese knotweed in a garden

Japanese Knotweed and the Law

It is an offence to allow Japanese Knotweed to spread. If Japanese Knotweed spreads from your property onto that of an adjacent landowner, you could be liable for costs and damages.  You could also be responsible for treatment of your neighbour’s property if it started on your land. So don’t just ignore it – save yourself time, money and stress by treating your Japanese Knotweed immediately. 

It's a criminal offence to cause the spread of Japanese Knotweed under Section 14(2) of the Wildlife and Countryside Act 1981 (WCA 1981). You could face a fine of up to £5,000 and/or 6 months imprisonment if found guilty in a Magistrate's Court, and up to two years imprisonment and/or an unlimited fine in a Crown Court although this is extremely unlikely.

The Environmental Protection Act (EPA) 1990, Duty of Care Regulations 1991 states that all material and soil contaminated with Japanese Knotweed must be disposed of as controlled waste.

You are not allowed to put any Japanese Knotweed material into any of your local council provided bins, or in public rubbish bins.  If taken off site, Japansese Knotweed must be disposed of as controlled waste in specifically licensed land-fill sites.  Also, be aware that cutting it down doesn’t kill it, the rhizomes (like roots) will survive and cutting will often make it more difficult to eradicate because many of the chemicals need to be applied to the leaves of the plant.

For further information on Japanese Knotweed legislation, please refer to the Environment Agency's code of practice ‘Managing Japanese knotweed on development sites'.


How to Get Rid of Japanese Knotweed?

Japanese Knotweed can actually be killed very quickly if the correct method can used; but can be difficult to kill if treated incorrectly. Methods to deal with Japansese Knotweed include herbicide treatment, excavation and removal, burial, root barrier membranes or combinations of these methods.  

Attempting to cut down the visible Japanese Knotweed plant can delay the eradication process. All new Japanese Knotweed plants are created by fragments of existing plants. A fragment of root as small as 0.8 grams can grow to form a new plant, so it’s important not to use a mower or strimmer as this will spread the fragments far and wide and will vastly increase the spread.

Japanese Knotweed can remain dormant it is usually best and most economical to treat the weed over a longer period of time using herbicides such as Glyphosate or Picloram.

The most frequent treatment plan options include:

  • Herbicides - The application of herbicide by either injection or spray is often the most efficient and cost effective option for the control of Japanese Knotweed.
  • Excavation & Removal - Although costly, excavating and removing Japanese Knotweed infested soil to a landfill site is effective and has the advantage of an immediate removal of the Japanese Knotweed infestation.  Ideally herbicide will have been applied to the stand before excavation.  The PCA guidelines recommend a minimum of 2 annual inspections before the site can be signed off as completely JK free - this is to allow for the re-growth of fragments that may have been missed.
  • Root Barrier Membrane - A root barrier can be installed that will encapsulate or provide a barrier against the Japanese knotweed on site to remove the cost of dig and dump or the risk of re-infestation from a neighbouring site.

C&F Japanese Knotweed Services

Our Japanese Knotweed services are comprehensive/affordable and include:

  • Surveys
  • Herbicide spray treatment and direct chemical injection
  • Feasibility studies
  • Consultancy only service on Commercial Projects – where excavations are undertaken by the client's own contractors
  • Warranties & management plans
  • Excavations & groundworks
  • Root barrier installations
  • Sealed membrane cells
  • GIS mapping

Next Steps

After an initial discussion and survey, our professional surveyor will provide a quote based on our Japanese Knotweed removal and treatment recommendations.

To find out more about the best solution to treat your Japanese Knotweed and to discuss our insurance and guarantee services, contact our team on 01582 507937. Alternatively, contact us online using our online contact form.

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