Herbicide treatment for Japanese knotweed

Japanese knotweed herbicide treatment may suit properties where the affected ground can remain undisturbed while a treatment programme is completed. It offers a way to manage growth without the machinery and extensive digging associated with excavation.

Knotweed Specialists UK assesses the infestation, selects an appropriate application method and plans follow-up visits. Treatment needs time and monitoring: a reduction in visible growth does not establish that every underground rhizome has been eliminated.

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Who is herbicide treatment suitable for?

This approach may suit homeowners protecting an established garden, landlords managing an affected property, and businesses or landowners without immediate construction plans in the infested area.

It is worth considering where excavation would cause substantial disturbance, provided the site can be managed throughout treatment. Access, neighbouring vegetation, watercourses and intended land use all need assessment.

If you plan to dig, extend a building or develop the affected ground soon, excavation and removal may be more appropriate. A Japanese knotweed site survey helps establish the options.

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How herbicide treatment works

Inspect and record the infestation

We assess visible growth and discuss access, past treatment and your plans for the property.
Plan the programme

The treatment plan sets out the proposed method, visit arrangements and monitoring. Sensitive features and any necessary permissions are considered.
Apply the treatment

Depending on plant growth and site conditions, treatment may involve foliar application or stem injection using an approved herbicide in accordance with its label.
Assess the response

Follow-up inspections check for regrowth and help determine whether further applications are needed.
Continue treatment and monitoring

The programme continues for the agreed period, with advice about avoiding disturbance of affected ground.

Applied to leaves

Foliar application

Herbicide is applied to the leaves. Application is planned around plant growth, suitable conditions and the need to protect surrounding vegetation.

Applied within stems

Stem injection

Herbicide is introduced into suitable stems. This can allow targeted application where the site assessment supports its use. It is not suitable for every stem or infestation, and follow-up remains necessary.

Japanese knotweed treatment guarantees

Your treatment agreement explains how regrowth is managed during the programme and what protection applies afterwards.

A 10-year insurance-backed guarantee is available on request for qualifying work, subject to policy terms. It provides protection for eligible treatment obligations if we cease trading and can be transferred to a new property owner.

We’ll explain when cover starts, what is included and any conditions before you proceed.

Find out about our insurance-backed guarantee here.

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COVERAGE

Areas We Cover

Hampshire
Sussex
Surrey
Dorset
Berkshire
Wiltshire
Somerset
Bristol
Gloucestershire
London
South Wales

What our clients say

      EXCELLENT  
   Based on 55 reviews 
    
 
 
 
   
 
 
       Posted on Google  
   
   Maree Jobson 
 
 
 
 Trustindex verifies that the original source of the review is Google. Knotweed Specialist Sam offers an expert service of removing and maintaining knotweed issues and keeping property owners  informed with reports and photos with 3 visits annually, I would highly recommend this business to anyone seeking advice and assistance with knotweed issues
  
 
      Posted on Google  
   
   Theresa Birtles 
 
 
 
 Trustindex verifies that the original source of the review is Google. Very good company to deal with. They are informative and approachable. They give clear advice and return every year to check that the Japanese Knotweed they treated is gone. They have made the process less scary and given us good advice along the way. Yes would recommend.
  
 
      Posted on Google  
   
   Karen Woods 
 
 
 
 Trustindex verifies that the original source of the review is Google. Sam and Pete have been professional throughout, answered all my questions and have gone the extra mile to assuage all my worries regarding the knotweed.  They arrived promptly for the first treatment and were really thorough in their approach, also giving me advice on how to manage the garden after their visit.  Would recommend their services without hesitation.
  
 
      Posted on Google  
   
   Jill Goodwin 
 
 
 
 Trustindex verifies that the original source of the review is Google. I contacted Knotweed Specialists UK Ltd to ask about a possible issue with running bamboo in the communal garden of our Southsea flats. Peter listened to my concerns and was able to advise (with no charge) and put my mind at ease. He told me that bringing in specialists would be an unnecessary waste of our money and explained how to contain the plant ourselves (or with help from a groundsman). When I told him that I wished my husband had been with me to hear his reassuring advice, he said he would be happy to talk to him as well. We took him up on this offer and are both very grateful we called this company. If we have issues in the future we will definitely be coming back.
  
 
      Posted on Google  
   
   Asuka Tsuchiya 
 
 
 
 Trustindex verifies that the original source of the review is Google. We needed a Japanese knotweed survey at short notice as part of a house purchase. Knotweed Specialists UK replied to our enquiry almost immediately, arranged access directly with the estate agent, carried out the survey within days of our first email, and sent us the written report — with photos and honest notes on the limitations of a visual survey — on the same day as the inspection.
Communication by email was easy and clear throughout, and the whole process was very professional.
Highly recommended, especially if you are buying a house and working to a deadline.
  
 
      Posted on Google  
   
   Harry Humby 
 
 
 
 Trustindex verifies that the original source of the review is Google. Great experience - Highly recommend!
Sam was extremely quick to reply and provided a really fast turnaround. He was incredibly helpful, friendly, and professional. If you need help with knotweed, these are definitely the people to call!
  
 
      Posted on Google  
   
   raj birring 
 
 
 
 Trustindex verifies that the original source of the review is Google. Very professional and helpful
  
 
      Posted on Google  
   
   Reece Residences 
 
 
 
 Trustindex verifies that the original source of the review is Google. Professional, easy to communicate with, and highly competent. I would recommend them for any knot weed related business.
  
 
      Posted on Google  
   
   Lucinda Brassey 
 
 
 
 Trustindex verifies that the original source of the review is Google. Both Pete & Sam have been very helpful in taking the time to talk to us and help establish whether we have a Japanese Knotweed problem.
  
 
      Posted on Google  
   
   geraldine isherwood 
 
 
 
 Trustindex verifies that the original source of the review is Google. Greatly appreciated the company's quick and professional approach to the work.

Frequently Asked Questions

How does herbicide treatment control Japanese knotweed?

Herbicide is applied to the leaves or injected into suitable stems, allowing it to move through the plant. Repeat treatment and monitoring help control growth and address regrowth over time.

How long does Japanese knotweed herbicide treatment take?

Herbicide treatment usually takes at least three years, with repeat visits to treat regrowth and monitor progress. The exact timescale depends on the infestation and how it responds to treatment. Following your survey, we’ll explain the recommended programme, including any additional monitoring, so you know what to expect.

What are the benefits and limitations of herbicide treatment?

Herbicide treatment generally causes less disturbance than excavation and avoids the cost of removing large quantities of soil. It may be a practical option when the land can be managed over time.

It does not physically remove the underground rhizome network. Ground disturbance can create a risk of regrowth or spread, so consult the treatment team before digging or moving soil from the affected area. Sites near water or protected habitats require additional consideration.

Use our control methods comparison if you are weighing up treatment against removal.

What affects the cost?

A quotation depends on the area and density of growth, accessibility, the application method, the number of visits and the duration of treatment and monitoring. Growth extending across boundaries can also affect the plan.

Ask which survey, reporting, monitoring and guarantee costs are included. A site assessment allows the programme to reflect the infestation and your requirements.

Is herbicide treatment suitable for my property?

It may be suitable if you want to minimise ground disturbance and have no immediate plans to excavate the affected area. A survey considers access, surrounding vegetation, sensitive features and your plans for the land.

Can I dig or landscape the area during treatment?

Speak to our team before disturbing treated ground. Knotweed rhizomes may remain underground, and digging or moving affected soil can cause regrowth or spread. If groundworks are planned, excavation may be a more appropriate option.

Does herbicide treatment come with a guarantee?

Your treatment agreement explains how regrowth is addressed and what guarantee applies. A 10-year insurance-backed guarantee is available on request for qualifying work, subject to policy terms. We’ll explain the cover and conditions before you proceed.

Herbicide treatment for Japanese knotweed

Who is herbicide treatment suitable for?

How herbicide treatment works

Inspect and record the infestation

Plan the programme

Apply the treatment

Assess the response