Do You Need Indemnity Insurance for Japanese Knotweed?
Japanese knotweed is notorious for its ability to damage homes, complicate property sales, and scare off mortgage lenders. But if you’re buying or selling a home, or have discovered this invasive plant on your land, you might be wondering whether indemnity insurance can help protect you.
In this guide, we’ll break down what Japanese knotweed indemnity insurance covers, when you might need it, and how it differs from typical home insurance policies. We'll also share expert tips to help you manage knotweed risks with confidence.
Worried about knotweed on your property?
What Does Japanese Knotweed Indemnity Insurance Cover?
While policies may vary, a comprehensive Japanese knotweed indemnity policy usually includes:
✅ Survey and Assessment Costs
Covers the cost of a professional inspection to confirm the presence or absence of knotweed.
✅ Treatment or Eradication
Includes chemical treatment or excavation if knotweed is discovered during the policy period.
✅ Property Repairs
Pays for damage to structures caused by knotweed, such as walls, patios, or outbuildings.
✅ Legal Expenses
Covers costs if you’re sued or must take legal action because of knotweed on your property.
✅ Mortgage Lender Protection
The policy may remain valid for the duration of the mortgage, protecting the lender’s interest.
Need help removing knotweed with a guarantee?
Who Needs Knotweed Indemnity Insurance?
This type of insurance is most useful for:
- Buyers purchasing property with no known knotweed history, but where the seller can't provide clear assurance
- Sellers who want to offer peace of mind to buyers when no knotweed is present but there’s uncertainty
- Mortgage lenders who require additional protection to approve a loan
Keep in mind: indemnity insurance is not suitable for properties already known to be affected by Japanese knotweed. If knotweed has been identified, you'll need a treatment plan and an insurance-backed guarantee from a professional removal company.
How Much Does Japanese Knotweed Indemnity Insurance Cost?
The cost varies depending on:
- Property value
- Proximity to known infestations
- Whether the policy covers just the homeowner or also the lender
In most cases, the one-off premium ranges from £200 to £500, offering protection for 5 to 10 years (or longer for lenders).
Does Home Insurance Cover Japanese Knotweed?
In most cases, no. Standard buildings or contents insurance will not cover:
- Damage caused by knotweed
- Removal or treatment of the plant
- Costs associated with legal claims from neighbours
Some policies may include legal expense cover, which might help with court costs in disputes related to knotweed. However, this is usually an optional add-on, not a default feature.
If your provider asks about Japanese knotweed, you are legally required to answer truthfully. Failure to disclose the presence of knotweed could invalidate your entire policy.
What About Property Sales and the TA6 Form?
When selling a property in the UK, you must complete the TA6 property information form, which includes the question: “Is the property affected by Japanese knotweed?”
Answering “No” or “Not Known” without evidence can expose you to risk. If knotweed is later discovered, the buyer may:
- Sue for misrepresentation or negligence
- Require you to pay for removal and property damage
- Claim for devaluation or legal costs
Indemnity insurance helps bridge this uncertainty. It reassures buyers and protects both parties if knotweed unexpectedly appears after the sale.
Can Japanese Knotweed Really Damage Buildings?
Yes. Japanese knotweed is incredibly persistent. Its underground rhizomes can:
- Grow up to 3 metres deep and 7 metres wide
- Exploit cracks in concrete, tarmac, or brick
- Cause structural damage to sheds, patios, drains, and extensions
While it’s rare for knotweed to destroy homes, it can weaken outbuildings and hard surfaces. Even minor damage can trigger lender refusals or legal disputes.
Not sure if it’s knotweed?
Will Insurance Cover Me If I’m Sued?
If a neighbour brings legal action against you due to Japanese knotweed spreading from your land, legal expenses insurance may help cover your defence costs.
Most home insurance policies offer legal cover as an optional extra. Typical coverage ranges between £25,000 and £100,000 depending on the insurer. However, this won't help if the insurer argues you failed to act once you were aware of the problem.
To avoid liability:
- Act quickly if you suspect knotweed
- Hire a licensed removal specialist
- Keep written records and treatment documentation
Should You Tell Your Insurer About Japanese Knotweed?
You are not obliged to tell your insurer about Japanese knotweed unless:
- They ask directly
- You’re making a related claim
- It affects your ability to insure the property
But honesty is always best. If knotweed causes later damage and you didn’t disclose it, you could be accused of negligence.
.JPG)
What Should You Do If You Discover Knotweed?
Don’t ignore it. The longer you wait, the more damage knotweed can cause, physically and financially.
Your next steps:
- Contact a PCA-accredited specialist
- Get a formal survey and management plan
- Request an insurance-backed guarantee
- Discuss indemnity insurance with your solicitor if selling
- Document every step taken to protect yourself legally and financially
At Japanese Knotweed Specialists, we offer comprehensive removal services, backed by 5–35 year guarantees. Our team is PCA-accredited and fully insured to help you handle knotweed safely, legally, and permanently.
Protect your property with professional support.
Frequently Asked Questions About Japanese Knotweed Insurance
❓ What makes indemnity insurance different from a treatment guarantee?
Indemnity insurance is a legal and financial protection tool, often used during property transactions. A treatment guarantee, on the other hand, is issued after professional removal and covers regrowth risk. Both serve different purposes but may be used together for full protection.
❓ Will indemnity insurance cover me if knotweed spreads from a neighbouring property?
No. Most indemnity policies only cover unknown pre-existing issues within your property boundary. If knotweed spreads from next door, you may need to pursue legal action, which may or may not be covered by legal expenses insurance.
❓ Can I get indemnity insurance after knotweed has already been found?
Generally not. Indemnity insurance is intended for properties with no current signs of knotweed. If the plant is present, the route forward is professional treatment and an insurance-backed guarantee.
❓ How long does a Japanese knotweed indemnity policy last?
Policies typically last 5–10 years for homeowners and for the full mortgage term for lenders. Always confirm the exact duration with your solicitor or provider.
❓ Do mortgage lenders accept indemnity insurance instead of removal?
Sometimes. If there’s no visible knotweed and a seller cannot confirm past presence, indemnity insurance can satisfy some lenders. But if knotweed is confirmed, lenders will usually demand a treatment plan and insurance-backed guarantee.
Final Thoughts
Japanese knotweed indemnity insurance is a valuable safeguard in property transactions. While it doesn’t prevent knotweed, it protects against its legal and financial consequences. Whether you’re buying, selling, or just want peace of mind, this insurance could save you from costly surprises down the line.
For existing infestations, however, only professional treatment combined with an insurance-backed guarantee offers lasting protection. At Japanese Knotweed Specialists, we’re here to guide you through every step, from identification to eradication and long-term cover.
About the Author: Adam Brindle
Adam Brindle is the Founder and CEO of Grounds Care Group, the parent company of Japanese Knotweed Specialists. With over a decade of experience managing invasive weeds like knotweed, bamboo and giant hogweed, Adam is a recognised expert in control, prevention and education.