Japanese Knotweed is an invasive plant species that can cause significant damage to homes, gardens, and other structures.
Early detection of Japanese Knotweed is crucial in preventing its spread and the destruction it can cause. One of the most effective ways to identify Japanese Knotweed is to locate its crowns.
In this blog post, we will discuss how to identify Japanese Knotweed crowns and why it’s important to take action.
According to the UK government, Japanese Knotweed costs the economy an estimated ÂŁ166 million ($230 million) per year to control and treat.

What Are Japanese Knotweed Crowns?
Japanese Knotweed (Fallopia japonica) is an invasive species of plant that has become a major problem in many parts of the world. The plant is fast-growing and can spread quickly, taking over areas of land and causing significant damage to buildings and infrastructure.
One way it spreads so rapidly is through its crowns, which are underground root systems that can grow up to seven feet deep into the soil. These crowns have rhizomes – horizontal stems – that send out shoots above ground, allowing new plants to sprout up even further away from the original root system.
Japanese knotweed crowns are incredibly hardy and difficult to eradicate due to their ability to regenerate even after being cut back or treated with herbicides; this makes them one of the most destructive invasive species on earth. To prevent further spread, it is important to identify and manage Japanese knotweed crowns quickly and effectively.
The Importance of Identifying Japanese Knotweed Crowns
It is important for land managers and property owners to be able to accurately identify the weed in order to take effective action against it. One of the most important features of Japanese knotweed identification is being able to recognize its crowns – the portion of the plant located above ground level.
Knowing what these look like will help you spot this troublesome weed before it becomes too established or spreads further afield.

Characteristics of Japanese Knotweed Crowns
The crown of Japanese knotweed is a distinctive feature, with its bright green colouring and hollow stems. The leaves are broad and shield-shaped, generally 6 to 8 inches long and typically arranged in an alternate pattern on the stem.
The flowers of Japanese knotweed are small white clusters which appear from late summer to early autumn. The plant stems are typically hollow and ridged with a reddish-brown colouring.
How Japanese knotweed crowns develop
Japanese knotweed (Fallopia japonica) is an invasive plant species found in many parts of the world. It can grow up to three metres tall and spreads rapidly through underground rhizomes, making it difficult to control.
As well as being a nuisance for gardeners, Japanese knotweed also causes damage to buildings and infrastructure due to its strong root systems. A key part of understanding how this weed behaves is understanding how its crowns develop over time.
As the plant matures, its crowns become larger and more complex. The crown is made up of two distinct parts – a vegetative layer and a reproductive layer. The vegetative layer consists of stems, leaves and flowers, while the reproductive layer consists of fruits, seeds and roots. As the plant continues to grow, these layers expand and intertwine, creating a complex crown.
The crown is essential for the plant’s survival as it helps to protect the roots from damage caused by animals or other environmental factors. The crown also regulates the amount of light, water and nutrients available to the plant. As the seasons change, so does the structure of the crown – in winter, for example, the plant will form a thicker, denser crown in order to conserve energy.

What to Do if You Identify Japanese Knotweed Crowns on Your Property
Identifying Japanese Knotweed on your property can be a daunting experience, as it is an invasive species that can cause extensive damage to buildings and other structures. If you suspect you have Japanese Knotweed growing on your property, there are steps you need to take in order to manage the infestation.
The most important thing to do is not panic – with proper identification and a plan of action, you can eradicate knotweed from your property. With the right knowledge and resources, managing this plant will become much easier. It’s essential that any treatment or management program for Japanese Knotweed begins immediately in order to prevent the further spread of the plant.
Step 1: The first step in identifying Japanese Knotweed crowns is to look for the tell-tale signs of its presence. These include an aerial stem and leaf structure with a hollow centre, as well as heart-shaped leaves that have serrated edges. It’s important to note that knotweed can easily be confused with other plants, so it’s important to take the time to carefully identify what you are dealing with.
Step 2: Once you have identified that the plant on your property is indeed Japanese Knotweed, it’s important to assess the extent of the infestation and determine how far it has spread. You can achieve this by mapping out where the plant is growing and taking into account the size of each infestation.
Step 3: Once you have identified the extent of the problem, it’s time to decide on a course of action. There are several methods that can be used for effective Japanese Knotweed control and eradication, including physical removal, chemical treatments, or a combination of both. It’s important to contact a professional if you are unsure which method would be best for your particular situation, as each has its own advantages and disadvantages.
Step 4: Japanese Knotweed can spread quickly, so it’s important to take steps to prevent further infestation. This includes avoiding spreading soil or other parts of the plant to other parts of your property and disposing of any parts you have removed from the site in a responsible manner. It’s also important to keep an eye on the area for further infestation, as knotweed can regrow quickly if left unchecked.
Taking these steps can help ensure that Japanese Knotweed is managed effectively on your property and that it does not spread to other areas. With proper identification, assessment, treatment, and prevention methods in place, you can rest assured that the infestation is under control.

How to deal with Japanese knotweed crowns
There are several methods for dealing with Japanese Knotweed crowns, including physical removal (digging out the root system) or chemical treatments (applying herbicides). Physical removal is often the most effective method, as it removes all of the underground root systems and prevents any future growth.
However, it is also very labour-intensive and can require a lot of time and effort to complete. Chemical treatments are easier to apply but may not be as effective in controlling the plant’s spread, as they cannot reach down into the crowns and rhizomes below ground.
Regardless of the method chosen, it is important to act quickly and thoroughly when dealing with Japanese knotweed crowns in order to prevent further spread.
Final thoughts
By learning how to identify Japanese Knotweed crowns, you can help prevent the spread of this invasive species and protect your property. If you suspect Japanese Knotweed is present on your property, it’s important to take action immediately.
Contact a professional for advice on the best course of action. Remember, prevention is key to stopping the spread of Japanese Knotweed, so make sure to follow prevention tips to keep your property free from this destructive plant.