Japanese Knotweed

A Bit About Knotweed

Japanese knotweed, is a large, herbaceous perennial plant of the family Polygonaceae, native to Eastern Asia in Japan, China and Korea.

In North America and Europe the species is very successful and has been classified as an invasive species in several countries.

Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not closely related. While stems may reach a maximum height of 3–4 m each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down.

This is a Time Lapse Video of Japanese Knotweed Growth

The leaves are broad oval with a truncated base, 7–14 cm long and 5–12 cm broad, with an entire margin. The flowers are small, cream or white, produced in erect racemes 6–15 cm long in late summer and early autumn.

How do I get rid of Japanese Knotweed
How do I get rid of Japanese Knotweed?

Closely related species include giant knotweed (Fallopia sachalinensis, syn. Polygonum sachalinense) and Russian vine (Fallopia baldschuanica, syn. Polygonum aubertii, Polygonum baldschuanicum).

Other English names for Japanese knotweed include fleeceflower, Himalayan fleece vine, monkeyweed, monkey fungus, Hancock’s curse, elephant ears, pea shooters, donkey rhubarb (although it is not a rhubarb), sally rhubarb, Japanese bamboo, American bamboo, and Mexican bamboo (though it is not a bamboo)


How do I get rid of Japanese Knotweed?

Treatment Programmes

As each circumstance is different IWM offer a range of treatment options for guaranteed results: Below are just some of the services we can offer.

Herbicidal Treatment Programme

Our most popular method of treatment using a herbicidal application. IWM operatives will conduct a minimum of 6 visits to ensure the complete removal of Japanese Knotweed. Our operatives have over 10 years’ experience using this application method to both the commercial and private residential sectors.

Herbicidal Treatment
Herbicidal Treatment

Stem Injection

Japanese Knotweed Stem Injection
Japanese Knotweed Stem Injection

Using the stem Injection technology our team applies a fast acting Herbicide that kills the plant at the core. This method is used particularly in sensitive areas to eliminate the potential to damage surrounding vegetation.



Stem injection can be applied in all weathers and is particularly useful to administer near water courses. IWM’s stem injection technology can also be applies to other hollow cane species such as Giant Hogweed and Himalayan Balsam

 Instant Knotweed Removal

Need Japanese Knotweed removal immediately? Using the instant eradication method IWM staff will fully excavate the affected land, including Rhizomes. This is then removed to an environment agency approved disposal site. This method offers the customer a quick complete solution for construction companies and land development.

IWM Instant Knotweed Removal
IWM Instant Knotweed Removal

On Site Burial & Translocation

Using an excavator method the Japanese Knotweed can be treated and controlled in a designated area on site. This can be either above or below ground depending on the customers wishes. This gives the customer the ability to continue with works at a much quicker pace and reduce transportation costs.
IWM recommend this option to our customers as part of our sustainability challenge


Weed Membrane
Weed Membrane

Using a geo textile membrane IWM will create a non-permeable barrier between a building or structure to ensure the containment of the infestation thus controlling the issue for treatment. This method can be particularly useful for people with boundary disputes or troublesome neighbours as well as helping planning applications.

Invasive weed management offer a nationwide service and have worked on various projects in Plymouth, London, Manchester, Sheffield, Leeds, Middlesbrough & York to name a few.

 Japanese Knotweed reports

IWM can offer professional & detailed Japanese Knotweed & invasive species reports. This could help with:

  • Buying or selling a property
  • Land disputes
  • SSSI (Sites of special scientific interest)
  • Commercial & domestic developments
  • Treatment advice
  • Peace of mind

Prices start from just £200+ VAT please call one of our office locations to arrange a site visit or email us at: info@invasiveweedmanagement.co

Buying or Selling a Property?

IWM can offer you a full report writing survey for any property you are selling or purchasing for your peace of mind. We have a qualified Invasive Weed surveyor who has an extensive knowledge of working with this and other troublesome species of invasive weeds.
If you’re having difficulty with a house sale or a surveyor has noticed Japanese Knotweed within 7 meters of your property IWM’s report will offer a comprehensive report writing service and can also offer a treatment package and Insurance backed warranty to satisfy all lenders.
Please call our Leeds office for a quote for a Japanese Knotweed report on 0113 2721590


Knotweed the Invasive Weed

Knotweed is listed by the World Conservation Union as one of the world’s worst invasive species.

The invasive root system and strong growth can damage concrete foundations, buildings, flood defences, roads, paving, retaining walls

and architectural sites. It can also reduce the capacity of channels in flood defences to carry water.

Japanese Knotweed Knot Weed Removal Invasive Weed Management
Japanese KnotWeed Removal

It is a frequent colonizer of temperate riparian ecosystems, roadsides and waste places. It forms thick, dense colonies that completely crowd out any other herbaceous species and is now considered one of the worst invasive exotics in parts of the eastern United States. The success of the species has been partially attributed to its tolerance of a very wide range of soil types, pH and salinity. Its rhizomes can survive temperatures of −35 °C (−31 °F) and can extend 7 metres (23 ft) horizontally and 3 metres (9.8 ft) deep, making removal by excavation extremely difficult.

The plant is also resilient to cutting, vigorously re-sprouting from the roots. The most effective method of control is by herbicide application close to the flowering stage in late summer or autumn. In some cases it is possible to eradicate Japanese knotweed in one growing season using only herbicides.

Trials in the Queen Charlotte Islands (Haida Gwaii) of British Columbia using sea water sprayed on the foliage have demonstrated promising results, which may prove to be a viable option for eradication where concerns over herbicide application are too great.

Two biological pest control agents that show promise in the control of the plant are the psyllid Aphalara itadori and a leaf spot fungus from genus Mycosphaerella.


People who fail to control the spread of invasive non-native plants such as Japanese Knotweed could be fined or receive anti-social behaviour orders (Asbos), the government says.

The weed is one of the most destructive plants in the UK.

The new rules mean people can now be fined up to £2,500 for failing to control it and other plants such as Himalayan balsam and giant hogweed.

And companies who fall foul of the law can be fined up to £20,000.


Read More on BBC NEWS

Knotweed in United Kingdom

In the UK, Japanese Knotweed is established in the wild in many parts of the country and creates problems due to the impact on biodiversity, flooding management and damage to property. It is an offence under section 14 of the Wildlife and Countryside Act 1981 to “plant or otherwise cause to grow in the wild” any plant listed in Schedule nine, Part II to the Act, which includes Japanese knotweed. It is also classed as “controlled waste” in Britain under part 2 of the Environmental Protection Act 1990. This requires disposal at licensed landfill sites. The species is expensive to remove; Defra’s Review of Non-native Species Policy states that a national eradication programme would be prohibitively expensive at £1.56 billion.

The decision was taken on 9 March 2010 in the UK to release into the wild a Japanese psyllid insect, Aphalara itadori. Its diet is highly specific to Japanese knotweed and shows good potential for its control.

In Scotland, the Wildlife and Natural Environment (Scotland) Act 2011 came into force in July 2012 that superseded the Wildlife and Countryside Act 1981. This act states that is an offence to spread intentionally or unintentionally Japanese knotweed (or other non-native invasive species).


Invasive Weed Management Leeds Specialise in Knotweed Treatment and Removal.

Knotweed Problem Contact US

We Currently have offices in Newcastle, Leeds, Sheffield, Hull, Liverpool, Manchester, Birmingham, London & Bristol. We operate throughout the United Kingdom (UK).