What is Japanese Knotweed?

Japanese knotweed, Fallopia japonica var. japonica is not native to the UK. It was introduced to the UK in the 1850’s as an ornamental plant, also suitable for rapid ground cover. It has certainly done that! It was still being planted in the UK as late as 1985 to provide ground cover and bank stability in difficult to access areas, such as railways.

This plant is common in Asia but does not cause anywhere near the number of problems it does here because in its native environment it is controlled by indigenous insects (psyllid beetles) and diseases.

In the UK though, it is not kept in check by nature, and unchecked can grow at up to 1 metre a month. The roots can grow up to 3 metres deep and 7 metres outward from the main stand of plants!

Where Does it Grow?

Japanese knotweed has spread dramatically across the UK and is common on, or near, the following areas: –

  • Rivers, streams and watercourses
  • Woodland
  • Roads and Motorways
  • Wasteland
  • Brown field sites awaiting redevelopment
  • Green field sites awaiting development
  • Railway lines and embankments
  • Gardens

How Do I Control It?

Japanese knotweed is controlled by various measures, and this depends on the severity of the outbreak, where it is, and environmental considerations such as nearby watercourses, trees and other vegetation that is to be retained.

The principle way we treat Japanese knotweed is by using herbicides as part of a treatment plan. This planned treatment can last up to 5 years. Sometimes treatments can be completed in as little as one growing season, subject to the type of treatment and extent of the outbreak.

Our favoured option wherever possible is to carry out a process called ‘stem injection’. This process involves using a specialist application gun to inject a controlled amount of herbicide directly into the base of the stem or cane of each plant, just above the root crown. By using this method at the correct time of year (around September time) we can achieve fantastic results. This system can reduce the need for, and number, of retreatments.

Outside this time frame, active growth can be successfully controlled by the foliar (leaf and stem) application of correct herbicides by certificated operators. We would always, however, recommend the September time treatment by stem injection, as this is the most effective treatment form.

There are various other means of controlling an outbreak, from creating bunded areas to removing contaminated topsoil, though we always try to avoid these options.

What Are My Legal Responsibilities?

As a landowner, you are not obliged by law to remove Japanese knotweed from your land. However, if it is affecting a neighbouring property and is causing problems then you DO have an obligation to deal with it. The same obligations apply to other invasive plant species such as Himalayan balsam and giant hogweed.

It is an offence under the Countryside and Wildlife Act 1981 to plant, or encourage Japanese knotweed (and other invasive plant species) to grow in the wild.

Waste plant material is classified as ‘controlled waste’ and should be disposed of as per the Environmental Protection Act 1990 (Duty of Care) regulations, and as you might expect, a license is required for this.

Our Services

We will attend your property or site to conduct a survey. Following this, we will prepare a written specification and treatment plan, with an indication of what your first and second year’s treatment costs are going to be. For the following year’s treatments recommended by us, we will also give you a guide to anticipated costs for the full treatment regime over the number of years, if this is relevant.

Once appointed we will provide you with full method statements, COSHH assessments and risk assessments prior to works being carried out.

We offer long-term warranties on our work, for planned long-term treatments. Please contact us for more information.

Not sure if you have Japanese knotweed?

Send us some pictures of your site, and try to include some close up shots and some wide angle photos. If it’s possible to identify Japanese knotweed from the information supplied, then we will. This service is carried out FREE of charge.

Recognition of our expertise by the Property Care Association (PCA)

YDC are members of the Property Care Association Invasive Weed Control Group. Managing Director Martin Hughes is formally qualified with the Property Care Association Invasive Weed Group qualification C.S.J.K. – Certified Surveyor in Japanese Knotweed. Matt Tucny, Co-Director, and Martin Hughes are both certified in the use of herbicides and their application methods, having the PA1 and PA6 (AW) national qualifications.

As a long-term member of PCA, Yorkshire Dampcourse (YDC) is pleased to have joined the Invasive Weed Control Group within PCA. You will find YDC listed in other PCA sectors on their website.

Whilst new to invasive weed control, YDC does not lack knowledge of invasive weed control mechanisms. Our lead person in this area is the director and owner of the company, who has a degree in agriculture and specialised in agronomy (the study of the growth and yield maximisation of crops). Weed control is crucial to this. We want to serve the “smaller” end of the invasive weed control market – perhaps the areas that larger companies find just too small. Helping estate agents, vendors, buyers, landlords and commercial property owners who are having Japanese knotweed (or other invasive weed) problems in their gardens or on their land is our target. The smallest plot we have treated so far is 7 x 5 metres! (Japanese knotweed): the largest is a stretch of riverbank along the River Aire (giant hogweed).

We expect to offer our clients treatment regimes based on stem injection and foliar herbicide applications – for which we are fully qualified and insured. We offer the suite of invasive weed control insurance and guarantee backup policies that are within the PCA Insurance Scheme. YDC also carries limited professional indemnity and consequential loss insurance. You can be sure that you are well protected!

All our work is carried out by our own employees, and we take quality and service to our customers very seriously.