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How long does it take to get rid of Japanese knotweed? 

How long does it take to get rid of Japanese knotweed? 


This invasive non-native plant is notorious for its tenacity, making it a significant concern for homeowners. In this blog, we’ll explore the factors influencing the timeline for eliminating Japanese knotweed and discuss effective strategies to ensure successful removal. 

Understanding Japanese knotweed: 

Japanese knotweed, an aggressive and fast-growing non-native invasive plant, is known for its ability to spread rapidly through its rhizome system. Its underground network allows it to regenerate quickly, making complete elimination a complex task. Understandably, as soon as most people find it growing on their property, they want to get rid of Japanese knotweed as quickly as possible.

Find out more about Japanese knotweed here. 

Dealing with Japanese knotweed on your property can be exceptionally daunting due to its notorious tenacity as an invasive non-native plant. This blog aims to shed light on the different factors that influence the timeline for eliminating Japanese knotweed, offering effective strategies to ensure successful removal. Recognised for its aggressive growth and rapid spread through its rhizome system, Japanese knotweed poses a significant concern for homeowners seeking to eradicate it completely. As we delve deeper into understanding this invasive species, we’ll explore the complexities involved in its removal process and provide insights into what to do if found on your property. 

Factors influencing the removal timeline: 

Infestation severity: 

The extent of the infestation significantly impacts the time required for treatment or eradication. Larger infestations often take longer to deal with as they will have deeper root systems, and will almost always require more treatment visits. Where access is challenging, or the knotweed has damaged buildings or landscaping features like walls, patios and drains, this adds complexity, and therefore time to the process of getting rid of knotweed.  

Treatment method: 

The chosen method of treatment or removal is probably the most significant factor in determining how long it will take to get rid. Chemical treatments, excavation, and professional removal services all have different timelines for effectiveness and depend on a variety of other factors, such as the plant’s growth cycle or access to the infested property or site. Japanese knotweed removal can take just days, but treatment using chemicals will take 3-5 years.  

Consistency and patience: 

Successfully eradicating Japanese knotweed requires consistency in treatment as well as patience. Quick fixes are possible where professional excavation is used to get rid of the knotweed and all affected soil, but a sustained effort is essential for long-term success, which includes follow-up monitoring for a few years. Unfortunately, most of our clients who try to remove knotweed themselves either ended up with regrowth or even worse, a bigger infestation on their hands! 

How long does Japanese knotweed treatment take? 


Herbicides are commonly used to control Japanese knotweed. However, these treatments typically require multiple applications over several growing seasons. It may take two to three years to see substantial results. A careful balance of chemical, applied at the right time in the right way is needed to achieve successful control. For this reason, many DIY attempts fail and will often result in sustained regrowth. Furthermore, DIY treatment won’t provide you with much of a legal defence if the knotweed spreads into your neighbours’ land and may cause problems when you come to sell your property. 


Physically removing the plant through excavation can offer quicker results, typically within days or weeks. However, digging out the plant’s rhizome system is notoriously hard to do. Japanese knotweed can grow 2 meters or more deep into the ground and spread several meters underground from the visible growth on top. This means a huge amount of soil must be excavated and worked through to get rid of the knotweed. This process is often beyond the capabilities of the average homeowner or gardener. To add to the problem of volume, knotweed also grows back from the smallest of root fragments left behind – meaning the knotweed is likely to grow back following amateur attempts at removal.   

Using a professional contractor will help you to get rid of knotweed quickly and effectively.  

Enlisting the help of professionals with expertise in Japanese knotweed removal will expedite the process, saving you both time and money in the long run.  

At Environet, our team has developed a range of different methods for Japanese knotweed treatment and removal. Residential properties need a specialist approach when it comes to Japanese knotweed removal, mainly because most residential buildings and gardens are smaller and closer together.  

Over the past 26 years, we have developed a range of trademarked approaches to remove Japanese knotweed including DART™ and Resi-Dig-Out™ (a scaled down version of our commercial Eco-Innovative Xtract™), as well as our own effective herbicide treatment formula. 

Getting rid of Japanese knotweed is a task that demands time, effort, and strategic planning. While the specific timeline varies based on factors like infestation severity and chosen removal method, you will always need to have the right tools and expertise to be able to remove Japanese knotweed effectively. Homeowners’ best course of action is to hire a professional company to create a tailored Japanese knotweed management plan to address the unique challenges. By understanding the factors at play and choosing the right approach, successful eradication is achievable, ensuring a knotweed-free landscape for the long term.  

Have you got a Japanese knotweed problem on your hands? Contact Environet’s team today on 01932 868 700 or email us at [email protected] 

Robert Spaceman

“We had a large stand of bamboo removed, thinned, contained and replaced. The customer service has been first class. Joe and Jason were fabulous and kept me well informed at all times”.