Upload Your Image & Identify Japanese Knotweed with AI
Simply upload your image that you want identified and our tool will be able to assist in the identification of Japanese Knotweed.
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If you have had confirmation that this is Japanese Knotweed, please contact us to book in a survey or speak to one of our specialists for expert advice
Please note. The AI-based plant identification tool provided on this website is sophisticated and continually improving, yet they are not without limitations. It may not always accurately identify certain plants, in particular rare species, plants with characteristics similar to multiple species, or plants photographed under sub optimal conditions. Please understand that we accept no liability for any inaccuracies in the identification provided by the AI tool or for any reliance placed on such information. We encourage users to utilise our AI tool for preliminary identification purposes, however we do not guarantee the accuracy of the information provided by the AI tool. For verification of the AI's identification, please contact us providing additional details or images so that our experts can identify it accurately and provide you with professional advice. It's important to note that precise identification may depend on various factors including, but not limited to, the plant's geographic location, habitat, and the time of year it was observed.
Why is it Important to Identify Japanese Knotweed Early?
Identifying Japanese knotweed early is crucial due to its invasive nature and resilience. While herbicide treatment can halt the above-ground growth, the roots, or rhizomes, can sustain life for up to 20 years.Left unchecked, Japanese knotweed can resurface spontaneously, particularly when the contaminated ground is disturbed by gardening or construction. Over time, this infestation can lead to various issues, including:
- Disruption of amenity land use
- Escalation of land use costs
- Structural damage to hard surfaces
- Property devaluation
- Legal complications
Why Do You Need an Expert for Japanese Knotweed Identification?
Accurate identification of Japanese knotweed is crucial to prevent its rapid spread and potential damage to your property and surrounding areas. Therefore relying on an expert for this task is paramount.
At Japanese Knotweed Specialists, our team of experts can conduct comprehensive surveys, offer visual identification, and utilise specialised methods such as dog detection surveys, particularly effective during winter months for underground detection.
Contact the experts at Japanese Knotweed Specialists today to discover how we can tailor a knotweed treatment and removal management plan specific to your property's needs.
Japanese Knotweed Identification Process
RICS Approved Survey
RICS (Royal Institute of Chartered Surveyors) surveys are carried out by one of our accredited surveyors here at Japanese Knotweed Specialists. We most commonly carry these surveys out in the warmer months, especially as people begin to prepare their gardens for summer, or as they winter-ready them.
Our expert knotweed identification survey looks for signs of Japanese knotweed and uses the latest RICS and PCA (Property Care Association) Guidance to provide you with an accurate and actionable report.
RICS Approved Dog Detection Survey
In winter months, we use sniffer dogs to help identify knotweed in areas of thick overgrowth or large expanses of land. Generally, dogs are used when knotweed is suspected but cannot be seen.
These highly trained sniffer dogs are able to recognise and identify the smell of Japanese knotweed roots and buds and can cover large expanses of land at rapid speed, quickly identifying knotweed before it takes over.
What Does Japanese Knotweed Look Like?
Japanese knotweed has several strong characteristics:
Japanese knotweed flowers appear in late summer, and are small, white and very delicate. You may see bees flocking to them, as they often bloom after most other flowers have died. The flowers grow on long thin spikes around 10cm in length.
Japanese knotweed leaves are up to 15cm in length and fairly flat. Arranged in an alternating pattern, the leaves begin a reddish colour in the spring before turning fully green in summer. They are shovel-shaped, although hybrid versions may appear more heart-shaped.
The stem of Japanese knotweed is a hollow culm, similar in appearance to bamboo externally. In spring, the shoots start out reddish-purple, before growing into green with red flecks and rings. In winter, they die back to being brown brittle canes which can be easily snapped.
In early spring, Japanese knotweed can be identified through often random but very hardy purple, reddish-brown shoots that appear through dead foliage. The sporadic growth can happen anywhere, including through pavement cracks and walls.
The root system of Japanese knotweed is very invasive, and can grow through house foundations, boundaries and more. The roots are thick, and while often found around 1m below the ground, they can be found up to 3m below ground.
In winter, Japanese knotweed loses its white flowers and leaves, leaving brown, hollow canes behind in its place. While these may appear dead, if left, they can last the winter and bloom once again in spring.
Japanese Knotweed Identification Video Guide
Download Our Japanese Knotweed Identification Guide
As the Japanese knotweed identification process can be challenging, depending on the time of the year and the conditions of the environment, we’ve developed a guide to help you understand the timeline of growth and change that occurs in this plant throughout the seasons.
Identification of Japanese Knotweed Throughout the Seasons
Japanese knotweed is a perennial plant, meaning its appearance changes with the seasons. It starts with small fleshy roots in the spring, potentially growing up to 10cm per day and over 3 metres high in the spring and summer, before dying back to brittle, leafless canes in the winter where it is less identifiable.
Japanese Knotweed in Spring
In early spring, the reddish-purple shoots begin to appear. These soon turn to smaller reddish-green leaves and begin to grow at a rapid pace as we head into early summer.
Growth will be sporadic, and shoots could appear anywhere, not necessarily near dead canes from the previous winter. By the end of spring, the knotweed will be a metre or so high and begin to turn a darker green.
Japanese Knotweed in Summer
In summer, when this invasive plant is at an average of between 2-3 metres high in full bloom, the spade shaped leaves and spiky stems with creamy white flowers make Japanese knotweed identifiable.
With the ability to grow up to 10cm a day in the height of summer, Japanese knotweed will be noticed by the end of August if it hasn’t already been. The combination of sheer height and density of Japanese knotweed makes it easily identifiable.
Japanese Knotweed in Autumn
The appearance of Japanese knotweed in autumn has very similar traits as in late August, as the flowers will potentially be in full bloom until early October.
Towards the end of October to November, the shield shaped leaves will start to wilt and turn yellow, and the stems will become dark brown in colour and start to become dormant, appearing brittle.
Japanese Knotweed in Winter
Around November, leaves will have fallen, and the dark brown canes will appear brittle, and may start to decompose. Whilst in winter Japanese knotweed remains dormant above ground, below ground the rhizomes are still present and will continue to spread. This is when our highly trained sniffer dogs are used to detect stubborn roots and buds underground.
Around February, the new season’s shoots may already begin to appear. These could be growing near clusters of dead stems, other foliage, or from cracks in cement or brick.
Do You Think Japanese Knotweed is Growing on Your Property?
If you suspect Japanese knotweed is growing in and around your property, request a survey from us today and we’ll investigate it for you.
Where Does Japanese Knotweed Grow?
Japanese knotweed is rife across the UK, with hundreds of active cases around the country. It has the versatility to grow anywhere, especially in areas where the soil has become contaminated. As it can spread very quickly, it’s also difficult to control if not treated correctly.
Some of the places you might find Japanese knotweed include:
- Near dead foliage or dead stems in your garden
- Around ornamental garden plants or vegetable plots
- Growing through cracks in cement or brick
- On new- build construction sites
- In overgrown gardens that have seen little maintenance
- In well-kept gardens
Fortunately, Japanese knotweed is not strong enough to grow through secure materials, but it can force its way through any broken building materials, including rubble. If it’s left to grow, it can lead to major structural damage. For example, it has the strength to move underground pipework or lift up paving slabs.
Whilst the plant might look pretty to some, it can majorly disrupt other plant life on your premises. Where it is able to rapidly grow, its density can starve other plants, killing them off altogether. This is another reason why you can be prosecuted if it spreads into the countryside. Even well-kept and groomed gardens can fall victim to the invasive weed – all it takes is a small piece of rhizome or contaminated soil to be mixed into your garden.
See More Japanese Knotweed Pictures
Don’t rely on guesswork, especially when it comes to such a destructive and costly plant. When attempting to identify Japanese knotweed, it’s helpful to look at pictures – many of which highlight just how invasive this plant can be.
But if you’re still unsure – always contact a specialist for a professional survey. Misidentifying Japanese knotweed can lead to costly and damaging consequences.
Frequently Asked Questions
What does Japanese knotweed look like when it begins to grow?
How Japanese knotweed looks when it begins to grow will depend on the time of year. Notable characteristics of Japanese knotweed to look out for include small white flowers, hand-sized shovel-shaped leaves and a zig-zag shape on the stem.
Can I identify Japanese knotweed myself?
While identification guides can help to spot the signs of the highly invasive knotweed, it's best to leave it to professionals to 100% confirm the presence of Japanese knotweed. Japanese knotweed can do vast amounts of damage when left alone, so it's best to avoid the consequences of misidentification.
Where am I likely to find Japanese knotweed?
Whether a residential or commercial location, Japanese knotweed won’t discriminate. You’re likely to find Japanese knotweed among your garden shrubs or even on building sites if the conditions are right. Japanese knotweed is a hardy, stubborn plant with strong roots, sinking deep into the soil wherever you may find it.
What’s the best removal method for Japanese knotweed?
Unfortunately, there isn’t a one-size-fits-all solution as there are multiple factors that need to be considered. From the landscape and local infrastructure that could be affected to the severity of the infestation, every instance is different. We will outline the methods we recommend per project once we have performed a survey.
Our Experts Can Identify Your Japanese Knotweed Problem Today
Japanese Knotweed Specialists are the leading invasive species identification and removal professionals in the UK, capable of treating and disposing of various aggressive plants including Japanese knotweed, bamboo and more.
If you suspect growth of Japanese knotweed on your property, you have a legal obligation to prevent it from spreading. Contact a specialist today to ensure peace of mind – we’ll help you recognise, identify and treat any infestations.
