If you’re a homeowner or gardener dealing with Japanese knotweed, you may be tempted to take matters into your own hands and attempt to treat the invasive plant yourself. While DIY treatment may seem like a cost-effective solution, it can come with serious risks. In fact, attempting to eradicate Japanese knotweed without professional help can lead to a number of problems, including legal issues, property damage, and even the spread of the plant.

One common mistake that DIY knotweed treatments often make is failing to properly identify the plant. Because Japanese knotweed can resemble other plants, such as bamboo or bindweed, it’s important to be certain that you’re dealing with the correct species before attempting to treat it. Misidentification can lead to ineffective treatment and the spread of the plant, as well as potential legal issues if the wrong plant is targeted.

Another risk of DIY knotweed treatments is the use of inappropriate chemicals or methods. While there are a variety of chemical treatments available, not all are effective or safe for use in residential areas. Additionally, improper application of chemicals can lead to property damage, harm to other plants and wildlife, and even personal injury. Without proper training and experience, it can be difficult to know which treatments are appropriate and how to apply them safely.

Japanese knotweed growing wildly on wasteland
Japanese knotweed growing wildly on wasteland

What is Japanese Knotweed?

If you are considering DIY Japanese Knotweed treatment, it is important to understand what you are dealing with. Japanese Knotweed (Fallopia japonica or Reynoutria japonica) is an invasive plant species that originates from East Asia. It was introduced to Europe in the 19th century as an ornamental plant but quickly became a problem due to its aggressive growth and destructive nature.


Japanese Knotweed is a perennial plant that can grow up to 3-4 meters tall. It has heart-shaped leaves that are arranged alternately on the stem. The leaves are around 10-20 cm long and 7-14 cm wide. Japanese Knotweed produces small, white flowers in late summer or early autumn. The plant is often referred to as “Godzilla weed” due to its ability to grow through concrete and tarmac.


One of the most distinctive features of Japanese Knotweed is its rhizome system. The rhizomes are underground stems that can grow up to 7 meters horizontally and 3 meters deep. This makes the plant incredibly difficult to eradicate, as even a small piece of rhizome left in the soil can regenerate into a new plant.


Japanese Knotweed can grow in a variety of habitats, including riverbanks, roadsides, and gardens. It prefers moist soil and can tolerate a range of pH levels. The plant is highly aggressive and can quickly outcompete native plant species, leading to a loss of biodiversity.

In summary, Japanese Knotweed is an invasive plant species that is difficult to eradicate due to its rhizome system. It can grow in a variety of habitats and is highly destructive to native plant species. If you are considering DIY treatment, it is important to understand the risks involved and seek professional advice if necessary.

Japanese knotweed pushes all the way up to a footpath
Japanese knotweed pushes all the way up to a footpath

The Risks of DIY Japanese Knotweed Treatment

Why DIY Treatment is Risky

If you’re considering DIY Japanese Knotweed treatment, you may want to think twice. While it may seem like a good idea to save money and take care of the problem yourself, there are many risks involved with DIY treatment.

Firstly, Japanese Knotweed is an invasive plant that is difficult to control. It has a rapid growth rate and can quickly spread, making it hard to remove. Without the right knowledge and tools, you may end up causing more damage than good.

Another risk of DIY treatment is the use of herbicides. Glyphosate, the most common herbicide used for Japanese Knotweed removal, can be dangerous if not used correctly. It can harm other plants and animals in the area, and if it gets into the soil, it can cause long-term damage.

Examples of What Can Go Wrong

There are many examples of what can go wrong with DIY Japanese Knotweed treatment. Here are a few:

  • Using the wrong herbicide: If you use the wrong herbicide, you may end up killing other plants in the area. This can be especially harmful if you’re trying to protect a garden or lawn.
  • Not protecting nearby plants: Even if you use the right herbicide, you need to protect nearby plants from the spray. If you don’t, they may be damaged or killed.
  • Smothering the plant: Some people try to smother Japanese Knotweed by covering it with heavy rocks or a tarp. While this may seem like a good idea, it can actually make the problem worse. Japanese Knotweed needs sunlight to photosynthesize, so if you cover it up, it may grow even faster.
  • Digging out the plant: Digging out Japanese Knotweed may seem like a good idea, but it’s a difficult and time-consuming process. If you don’t remove all the roots, the plant will grow back.
  • Hiring unqualified professionals: If you decide to hire professionals to remove the plant, make sure they’re qualified and experienced. Some companies may claim to be experts in Japanese Knotweed removal, but they may not have the necessary skills or equipment.

Overall, DIY Japanese Knotweed treatment is risky and can lead to more problems than solutions. If you want to get rid of Japanese Knotweed, it’s best to hire a professional who knows how to do it safely and effectively.

Different methods can be used to control Japanese knotweed
Different methods can be used to control Japanese knotweed

Control Methods

When it comes to controlling Japanese Knotweed, there are two main methods: Chemical Control and Non-Chemical Control.

Chemical Control

One of the most common methods of controlling Japanese Knotweed is through the use of glyphosate-based chemicals. Glyphosate is a broad-spectrum herbicide that targets the plant’s root system, effectively killing it. Glyphosate-based chemicals can be applied using a sprayer or a paintbrush, depending on the size and location of the infestation.

It is important to note that glyphosate-based chemicals can be harmful to other plants and animals, so it is important to use them with caution. When using glyphosate-based chemicals, it is important to follow the instructions carefully and wear protective clothing, including gloves and a mask.

Non-Chemical Control

Non-chemical control methods include pruning shears, excavation, smothering, and covering. Pruning shears can be used to cut the plant at the base, effectively killing it. Excavation involves digging up the plant and its root system, which can be an effective method for small infestations. Smothering involves covering the plant with a tarp or other material to prevent it from getting sunlight. Covering involves planting a dense ground cover to prevent the plant from growing.

It is important to note that non-chemical control methods can be time-consuming and may not be as effective as chemical control methods. Additionally, non-chemical control methods may not be suitable for large infestations.

Insects have also been used as a form of non-chemical control for Japanese Knotweed. The insects feed on the plant and can help to reduce its growth. However, the use of insects as a control method is still in the experimental stage and may not be suitable for all infestations.

Overall, when choosing a control method for Japanese Knotweed, it is important to consider the size and location of the infestation, as well as the potential risks and benefits of each method.

Japanese knotweed broken through a fence onto another property and possible legal action will ensue
Japanese knotweed broken through a fence onto another property and possible legal action will ensue

Legal Considerations

Laws and Regulations

When it comes to Japanese Knotweed treatment, there are several laws and regulations that you need to be aware of. Japanese Knotweed is classified as “controlled waste” under the Environmental Protection Act 1990, which means that it must be disposed of in a specific way. You cannot simply burn it or throw it in the trash. Instead, you must take it to a licensed landfill site or have it removed by a licensed waste carrier.

In addition, the use of glyphosate herbicide for Japanese Knotweed treatment is regulated by law. The Chemicals Regulation Division of the Health and Safety Executive (HSE) regulates the use of glyphosate herbicide and requires that anyone using it must be trained and certified. Failure to follow these regulations can result in fines or legal action.

Impact on Property Value

Japanese Knotweed can have a significant impact on the value of your property. Mortgage lenders are often reluctant to lend money on properties with Japanese Knotweed, as it can cause structural damage to buildings and reduce the value of the property. In some cases, lenders may require a specialist report to be carried out to assess the extent of the Japanese Knotweed infestation and the potential risks it poses.

If you decide to treat Japanese Knotweed yourself and do not follow the correct legal procedures, you could be held liable for any damage caused to your property or neighbouring properties. This could result in legal action being taken against you, which could be costly and time-consuming.

In addition, if you fail to disclose the presence of Japanese Knotweed when selling your property, you could be sued by the buyer for misrepresentation. This could result in you having to pay damages or even having the sale of your property cancelled.

Overall, it is important to be aware of the legal considerations when treating Japanese Knotweed. Failure to follow the correct procedures could result in fines, legal action, and a significant impact on the value of your property.

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