Introduction
Spring is here, and so is Japanese knotweed season. As temperatures rise, this highly invasive plant begins to emerge from dormancy, growing aggressively through gardens, driveways, and even structural weak points.
Given the speed at which knotweed grows – early detection is crucial. If left unchecked, Japanese knotweed can lead to property devaluation, legal issues, and costly removal treatments. But how can you spot it before it becomes a major problem?
Here’s everything you need to know about identifying Japanese Knotweed in March to May – and what to do if you find it.
What Does Japanese Knotweed Look Like in Spring?
Unlike its tall, dense summer growth, Japanese knotweed starts off as almost undetectable shoots in the undergrowth and can be hard to see. Look out for these early warning signs:
Red or purple shoots – Emerging from the ground, these resemble asparagus spears with reddish-brown tips.- Rapid growth – Shoots can grow up to 10cm per day once established.
- Bamboo-like canes – As it matures, stems become fleshy with hollow centres, jointed, and green with purple flecks.
- Shovel-shaped or shield-like leaves – New leaves unfurl as deep red to start with but quickly turn bright green, growing in a zig-zag pattern along the stem.
If you spot any of these signs, don’t ignore them – early action is key.
Where Does Japanese Knotweed Grow?
Japanese knotweed will grow pretty much anywhere and in nay soil or climate, but it thrives in gardens, driveways, riverbanks, railway embankments, and old construction sites. Check these high-risk areas:
- Near walls and fences – Knotweed can exploit weak points in structures.
- Paving, patios, and driveways – Look for cracks or lifted slabs, which may indicate underground rhizome growth.
- At the edge of water sources – Riverbanks and canals are common hotspots.
- Around disturbed soil – Old building sites often contain contaminated soil, leading to unexpected infestations.
Why Early Detection Matters
Ignoring Japanese knotweed can lead to serious issues, including:
Property devaluation – Many mortgage lenders refuse loans on properties with untreated knotweed.- Legal disputes – Homeowners can be held liable if knotweed spreads to a neighbour’s land.
- Structural damage – While knotweed won’t break through solid concrete, it exploits cracks and weaknesses in walls, drains, and foundations.
The earlier you detect and address Japanese knotweed, the easier and cheaper it is to remove.
Think You’ve Found Japanese Knotweed? Here’s What to Do
If you suspect Japanese knotweed on your property, follow these steps:
- Don’t cut it down – This can stimulate regrowth and spread the plant further.
- Don’t dispose of it in garden waste – Knotweed is classified as controlled waste under UK law and must be disposed of professionally.
- Don’t attempt DIY removal – The root system can spread underground, making it extremely difficult to eradicate without professional treatment.
- Book a professional survey – A specialist can confirm the presence of knotweed and provide a treatment plan with an insurance-backed guarantee.
Acting early can save you thousands in removal costs and prevent legal headaches.
How to Prevent Japanese Knotweed from Spreading
Even if you don’t currently have Japanese knotweed on your property, staying vigilant can help prevent future problems.
- Check neighbouring properties – If knotweed is nearby, it could spread underground.
- Monitor gardens and driveways – Regular inspections between March and May help catch early growth.
- Use professional monitoring services – Annual checks can detect early growth before it becomes a serious issue.
Conclusion
Japanese knotweed is one of the most destructive and fast-spreading invasive plants in the UK, but early detection and professional treatment can prevent serious damage.
Spring is the best time to act – if you notice any of the early warning signs, don’t wait. Book a professional Japanese Knotweed survey before it takes over.
Concerned about Japanese knotweed? Get expert advice today.