Introduction
Japanese knotweed (Reynoutria japonica, syn. Fallopia japonica) is one of the UK’s most notorious invasive plants. Its rapid growth, destructive underground rhizome system, and legal implications make it a serious concern for homeowners, developers, and local authorities.
At Japanese Knotweed Elimination Ltd, we’ve pulled together this comprehensive guide answering the top 60 questions about Japanese knotweed—from how to identify it, to treatment, disposal, and the impact it can have on your property.
Identification: How to Spot Japanese Knotweed
-
What does Japanese knotweed look like?
Bright green, shield-shaped leaves arranged in a zigzag pattern along bamboo-like stems with purple speckles. In late summer, it produces creamy-white flowers. -
Does it look different in different seasons?
Yes—red asparagus-like shoots in spring, tall green canes in summer, flowers in late summer, yellowing leaves in autumn, and dead brown canes in winter. -
How do I know it’s not bindweed or dogwood?
Bindweed climbs, knotweed is freestanding. Dogwood has solid woody stems, knotweed has hollow, speckled canes.
👉 Learn more about Japanese knotweed identification
Removal & Treatment: How to Get Rid of Japanese Knotweed
-
Can I remove it myself?
Small patches can sometimes be DIY treated with glyphosate, but most infestations need professional treatment for full eradication. -
What are the best methods?
-
Professional herbicide treatment (3–5 years, insurance-backed guarantee available)
-
Excavation & disposal (fast but costly)
-
Combination approaches (most effective long term)
-
-
What happens if I ignore it?
It spreads aggressively, can damage driveways, drains, and walls, devalue property, and lead to neighbour disputes.
👉 See our treatment options and request a free site survey
Legal & Property Issues: Know Your Responsibilities
-
Is it illegal to have Japanese knotweed?
No—but it is illegal to let it spread onto neighbouring land. -
Do I have to disclose it when selling my house?
Yes. The TA6 Property Information Form requires sellers to declare whether knotweed is present. -
How does it affect mortgages?
Many lenders won’t approve mortgages without a professional management plan and insurance-backed guarantee.
👉 Download our guide to Japanese knotweed and property sales
Impact & Spread
-
How invasive is it?
Extremely—its rhizomes can spread 7 metres horizontally and 3 metres deep, regenerating from fragments as small as 1cm. -
Can it grow through concrete?
Not solid concrete, but it can exploit cracks and weaknesses. -
Where is it most common?
Across the UK—especially in Wales, the South West, and urban areas.
Health & Safety
-
Is it poisonous?
No—unlike Giant hogweed, it doesn’t cause burns or rashes. -
Is it edible?
Yes—young shoots taste like rhubarb, but never eat knotweed that may have been treated with herbicide.
General FAQs
-
Where did it come from?
Japan, China, and Korea—introduced to the UK in the 19th century as an ornamental plant. -
Why is it such a problem here?
No natural predators, aggressive growth, and resilience of its rhizome system. -
Who can I contact for help?
A professional contractor who is PCA (Property Care Association) registered—like Japanese Knotweed Elimination Ltd.
Conclusion: Professional Help is Key
Japanese knotweed is one of the UK’s most complex and costly invasive species. While DIY methods can suppress it, complete eradication requires professional expertise and long-term management.
At Japanese Knotweed Elimination Ltd, we provide:
✅ Free identification services
✅ Professional treatment plans
✅ Insurance-backed guarantees
✅ PCA-registered expertise
📞 Call us now:
Request a Free Site Visit
Fill in the form below and one of our local team of specialists will get back to you within 24 hours, usually sooner.