Japanese Knotweed Treatment and Control in Swansea by Specialists – Green Leaf Remediations

Do you have knotweed at your property? Have you read how this will probably set you back £1,000’s? how it might affect your mortgage or your ability to sell your own home? Please do not fret, Green Leaf Remediation & Tree Services offers expert advice and solutions for the treatment and control of Knotweed in Swansea, and be reassured it does not cost as much as you may think. Call your local Knotweed expert on 01269 591651 or call Carwyn’s mobile on 07531142316.

Knotweed is a perennial weed that will grow and spread quickly if it is not controlled. The weed suppresses all the other plants growing close to it from the crown and rhizomes (root system) which spread extensively below the ground. The shoots die off above ground in the winter and re-emerge above ground again at the end of springtime, early summer. Any effectively established shoots can grow more than 9ft high and can colonise the soil within a few years making it extremely difficult to control. There are various articles that say you could eliminate the roots with chemical substances, however, you will need an NPTC qualified person to work with any chemicals as a result of new legislation which covers the management, removal and control of Knotweed. There are several misconceptions that say you can remove it yourself, however, this is an extremely hard and intricate procedure and in most cases, not successful unless you make use of an expert. In the peak of the growing season, 60% of the Knotweed plant has its roots underground, so removal is incredibly difficult. It also spreads wildly from one tiny fragment of crown or rhizome. Removing the species without extensive knowledge has a very high chance of spreading the plant to other regions of the soil which were previously unaffected.



How do I eliminate Knotweed?

There are several methods of elimination and control of Knotweed and a specialist will be able to give you advice on the best and most effective method.

Stem-Injection is usually a low impact approach to removal and there is little probability of disturbing or killing the plants growing close to it. The stem injection method is used for smaller areas of Knotweed where it has established itself amongst plants and vegetation that you want to keep. It’s also a technique normally applied when Knotweed is close to a watercourse. The stem injection approach works extremely well in dry or inclement weather conditions. The soil cannot be disturbed following the treatment.

Foliar Spray Application is often employed and is among the most favourable control strategies along with stem injection. The process can be used to manage and control the Knotweed over several growing seasons. Depending on the size of the area of invasive species it is frequently sprayed 2-3 times in the first year and once in the following years. The chemical used is an Environment Agency approved herbicide and requires dry weather, as well as the soil to remain undisturbed in subsequent years in order to work.

Weed Wiping Method is the leaves of the plant being wiped with a sponge which is soaked with the necessary herbicide. It’s a low impact treatment and doesn’t kill or bother the foliage adjoining it, however, its use is dependent upon how big the area of knotweed is.

Bund/Stockpiling Method is a blended treatment making use of stem-injection or foliar application, followed by digging up the underground material and removing the soil and materials to a different location where the emergence of ‘new shoots’ can be subjected to additional herbicide application. This approach can be used on sites where you need the removal of the knotweed to be fast and not done over several seasons so is, consequently, specifically good for building plots and development sites as work can proceed without delay.

Cell Burial/Root Barrier Method is a treatment used when there is adequate space on site to create a cell burial or utilising a root barrier to prevent the substantial costs of transporting the soil and waste to landfill. Cell burial buries the Knotweed stem fragments and giant knotweed plant to a minimum depth, or if encapsulated inside a geomembrane it can be closer to the surface of the ground. Root barriers can be installed both vertically and horizontally when there is a danger of cross-boundary contamination. Again, an approach most often used on development sites when building work needs to commence quickly.

Excavation & Removal Off-Site is a legitimate and fast control alternative which has its advantages for development sites if performed correctly, however, many Knotweed control experts are not not advocates of it as it raises considerable logistical complications. The challenges are it comes with a higher than normal chance of invasive Knotweed spreading in addition to the cost of securely and safely transporting the entire root and plant to a designated landfill site. There is also a duty of care required under the Environmental Protection Act (EPA) 1990. In summary excavation and removal must only be used as an absolute last resort.

Is Knotweed Harmful to Dogs, Cats and People?

Is Knotweed Poisonous to Dogs, Cats and Humans? SwanseaIn simple terms,  it isn’t poisonous or harmful to dogs, cats, humans or any other animals like some other very invasive plants. It’s not harmful to touch, however, always use extreme care when close to it to prevent inadvertently allowing it to spread.

It is known as ‘poisonous’ by developers and homeowners due to its highly invasive growth, ability to spread from any tiny particle left and how difficult it is to eliminate entirely.

Some Knotweed Misconceptions (several of which are exploited by some companies for financial gain)

  • “It will grow through solid concrete”
  • “It will destabilise foundations”
  • “It will cause structural damage”
  • Property affected by this invasive plant is not mortgageable

knotweed removal Swansea before and after

Essentially, if the previous groundwork or construction has been performed to a satisfactory standard then Knotweed is not going to grow ‘through solid concrete’, it will not destabilise solid foundations and it is highly unlikely to ‘cause’ structural damage. In fact, these claims are misleading, to say the least.

Nonetheless, in certain situations, when the foundations or concrete are old, badly constructed and have pre-existing cracks or fractures within, then invasive Knotweed species will unquestionably make use of any weak point in its pursuit of light and water and will swiftly establish itself, whilst exacerbating the initial fracture and potentially cause the structure to disintegrate.

Green Leaf Remediation Specialists cover the whole of South Wales (including Swansea, Cardiff and Newport), West Wales up to North Ceredigion & Powys and throughout South Glamorgan & Gwent. In addition, we carry out contracts in the West Country, as far North as Shropshire and into the Midlands & Birmingham areas.

We are a fully qualified Certificated Surveyor (JKCS), family-run business. We specialise in managing invasive Knotweed, other invasive plant species and ‘general nuisance weeds’ that are found in the United Kingdom for residential premises and property development sites.

We also offer tree services, such as pollarding, crowning, pruning, felling, through our NPTC chainsaw operators, all of whom possess a vast amount of practical experience in the forestry industry.


Our Qualifications & Accreditations include:

  • City & Guilds NPTC Level 2
  • Principles of Safe Handling & Application of Pesticides (PA1/ PA6)
  • Principles of Safe Handling & Application of Pesticides near water (PA6AW)
  • Herbicide Stem Injection
  • Property Care Association
  • The Control & Eradication of Knotweed Surveyor’s Training Course
  • Qualified Technician (PCAQT) in Japanese Knotweed
  • Accredited Surveyor in Japanese Knotweed

Whilst there are several companies who operate within the UK weed control industry who will be respectable, knowledgeable and thorough professionals, you will find, regrettably, lots of companies who claim to have the experience, qualifications and accreditations to eradicate, eliminate and control the invasive native species and ornamental plant at a low cost. Nonetheless, we would advise anyone to exercise extreme caution and to make sure that the service provider/business you enlist to carry out the control programme are qualified to do so and they abide by the industry codes of practice and have the necessary experience and insurance to do this.

Call us at the office on 01269 591651 or call the business owners personal mobile on 07531142316 and one of our knotweed experts in Swansea can answer any queries you may have and also arrange a site visit.

Japanese Knotweed FAQ’s

Where does knotweed grow?

It is also known as Fallopia, Bamboo and Peashooters and it was brought to Europe to be grown in botanical gardens in the middle of the 19th century by a German-born botanist. It was then sold commercially to homeowners, businesses, commercial properties and gardens and this is how and when it started to spread within the UK.

The simple answer is, it can grow anywhere, you may think it’s more prevalent in the countryside, however, this is not the case. It is found in towns, cities and the countryside and will quickly grow and take over if it is not controlled. 

When to Remove Japanese Knotweed?

It should be managed and controlled as soon as you are aware that it is there as it will spread very quickly. You should not attempt to remove it yourself as you could cause it to spread even further due to tiny tiny fragments of crown or rhizome which will spread quickly and widely. 60% of the knotweed weeds roots are underground, so this makes removal very difficult if not impossible if you don’t have the experience to do it. 

Call us and one of our Knotweeds specialist in Swansea will arrange a free home survey.

What should you do if you find Knotweed?

If you find or think you have Japanese knotweed and you own the land it is your responsibility to control it. You should contact a qualified NPTC person or company who has the experience and knowledge to use the correct and right method of removal for you and your property and they will come out to your property and assess it. Removing or disposing of Japanese Knotweed without the right experience and knowledge will almost always cause it to spread, therefore, it is vital that it is dealt with by a qualified specialist who can advise you on the most effective way to remove it.

The disposal of knotweed is classed as “controlled waste” under the Environmental Protection Act 1990, and this means it has to be disposed of at a licensed landfill site at a cost. A knotweed specialist will have the qualifications, experience and knowledge to do this.

What qualifications should a specialist have for the removal or control knotweed?

  • City & Guilds NPTC Level 2
  • Principles of Safe Handling & Application of Pesticides (PA1/ PA6)
  • Principles of Safe Handling & Application of Pesticides near water (PA6AW)
  • Herbicide Stem Injection
  • Property Care Association
  • The Control & Eradication of Knotweed Surveyor’s Training Course
  • Qualified Technician (PCAQT) in Japanese Knotweed
  • Accredited Surveyor in Japanese Knotweed

How do you permanently get rid of knotweed?

There are different methods of removal and control and a specialist will advise you on the best course of action for your property or land. Above we have detailed the different control and removal methods. Management and control is the most cost-effective way of ensuring the knotweed has less of an impact. Complete removal is possible, however, this requires more extreme actions. We can advise on this once we have visited the site.

Will Roundup kill Japanese knotweed?

Roundup has been known to kill Knotweed in some very few cases, however, it will also kill the plants and grass around it and it doesn’t have the strength of the chemicals that a specialist would use. Often knotweed has to be treated over several seasons and roundup will most likely only kill the foliage and flowers and not get into the roots which is where and how it spreads so quickly. You will need an NPTC qualified person to work with any chemicals as a result of new legislation which covers the management, removal and control of Knotweed.

Can I kill Japanese knotweed myself?

It is very unlikely you will kill or eradicate knotweed yourself and in most cases when it is attempted without experience it is more likely to encourage the weed to spread further. You should always use a qualified knotweed specialist as they will have the experience to know the best method of removal and control for your property and your circumstances, as well as using controlled chemicals.

How deep do Japanese knotweed roots go?

It’s crown and rhizomes (root system) suppress the plants growing around it and it spreads extensively and quickly. Well-established shoots often grow more than 3 metres high and can colonize the soil quickly in the height of its dominant growing season. 60% of its roots are in the soil underground and can grow up to 7 metres horizontally from the plant. This is the part of the weed that is most spreadable and as little as 0.7g will create a new knotweed plant.

Does salt kill knotweed?

Salt does not kill knotweed and only specialist chemicals used in a controlled manner by a qualified specialist will eradicate it and or control it.

Call us either at our offices on 01269 591651 or, as we like to offer personal service, please telephone the business owners mobile on 07531142316 and one of our knotweed experts in Swansea can answer any queries you may have and also arrange a site visit.