Many homeowners are asking the question, “Can Japanese Knotweed devalue my house?”

It is no secret that Japanese Knotweed is a highly invasive plant that can cause serious damage to both your home and your wallet.

The good news is that there are steps you can take to prevent Japanese Knotweed from devaluing your home. In this guide, we answer this essential question and aim to calm your fears and provide actionable insight to resolve this potential disaster.

How does Japanese Knotweed devalue a house?

It is estimated that Japanese knotweed will devalue a property by 10-15%. If you want to sell your property, it will be much more difficult if there is knotweed growing on the property. If you speak to several agents in your area they will tell you this is true. House prices can fall even further if other buyers are aware of its presence (maybe by looking at selling prices in your area).

If your house does sell and you have knotweed, your buyer will likely want to remove it and the easiest way to do this is by spraying it with chemicals.

Depending on how much knotweed there is and whether you agreed to sort this out before the sale went through, the buyer may ask for a reduced purchase price or insist that you pay for its removal.

Knotweed is a very expensive weed to remove so you may have to agree to this. This can lower the sale price of your property even more.

What to do when you spot Japanese knotweed?

The way around this is to get knotweed identified by a Chartered Surveyor, negotiate with your Sellers and Buyers or carefully consider whether it will devalue your home.

A surveyor will be able to tell you what can or cannot be done, whether the knotweed is present on your land with permission (or not) and if it has spread from a neighbour’s garden. You may need to get expert evidence for this in court if knotweed causes damage which you want to be sorted out before exchanging contracts.

It is always best to discuss this with your conveyancing solicitor and the other party. The Survey will cost around £280 but it may save you a lot of money in the long run if knotweed is discovered and it devalues your property or causes damage that requires professional assessment.

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Can Japanese knotweed devalue my house – quite simply yes

Can I get insurance if my house is affected by Japanese Knotweed

Japanese Knotweed is an invasive plant that can cause a lot of damage to your property. If you are affected by it, you may be wondering if you are covered by insurance. Unfortunately, most policies do not cover damage caused by Japanese Knotweed. However, there are some exceptions, so it is worth checking with your insurer to see if you are covered.

Here we look at common insurance policies and whether they cover Japanese Knotweed:

House Contents Insurance: Most contents insurance will not cover damage caused by Japanese Knotweed. However, there are a couple of insurers who may offer limited content coverage for this type of damage. It’s always worth checking with your insurer to see if they make an exception.

Buildings Insurance: Most building insurance will not cover damage caused by Japanese Knotweed, though there are a few insurers who may offer limited cover. It’s always worth checking with your insurer to see if they make an exception.

Landlord Insurance: If you’re a landlord and your tenant has brought Japanese Knotweed onto the property, you will not be covered by most landlord insurance policies. You may want to check with your insurer to see if they make an exception.

There are some specialist policies that cover landlords for damage caused by Japanese Knotweed so it is always worth checking with your insurer to see if they make an exception.

Home Emergency Cover Insurance: If you suffer damage caused by Japanese Knotweed, most home emergency cover policies will not cover the cost of removing it. However, there are some home emergency cover policies that may cover the cost of Japanese Knotweed removal, though this normally has to be an emergency situation.

Japanese Knotweed Removal Insurance: If your insurer offers limited Japanese Knotweed damage cover, it’s likely that you will only be covered for “emergency remedial work” only. If you are planning to remove Japanese Knotweed yourself, or via a specialist company, this may be a suitable option for you. However, if the damage is more extensive and your insurer does not make an exception, it’s unlikely that your insurer will pay for part of the cost of removal.

Note: Some policies may not specify whether Japanese Knotweed is covered or not. If your insurer does not state that it is excluded, you should assume that the policy will provide cover for Japanese Knotweed. However, as insurers can change their terms and conditions at any time it’s always worth checking with them to see if they make an exception.

How to spot Japanese Knotweed on your property

If you’re buying a property, it’s important to know what to look for before you sign on the dotted line. One of the most damaging plants you can have on your property is Japanese knotweed. It can damage foundations, walls, and even pipes. Here are some tips on how to spot it and what to do if it’s already on your land.

Japanese knotweed can grow anywhere, especially in gardens. It’s a weed which you want to look out for before buying property up. The first thing to do is to have your soil tested by an expert on Japanese knotweed. They are very expensive, so it might be best to switch the test to the new owner of the house if the problem has already occurred.

The reason you need to know about the existence of Japanese knotweed on your new property is that it can cost up to £5,000 not only to clear it but also to maintain it. It’s a huge job, and insurance companies will not pay out if they find out you knew about it beforehand.

Home overgrown with weeds and losing value if not dealt with
Home overgrown with weeds and losing value if not dealt with

What does Japanese knotweed look like

Here are some things to look out for when looking at a new property. If you spot these, then that’s definitely an indication that there is Japanese knotweed on the land.

  • The leaves are broad and flat with jagged edges; they can grow up to 40cm long and 20cm wide, but this depends on where it is growing (in the shade or in the sun, etc.).
  • If you touch one of the stalks, it will snap very easily. This is because they are hollow and full of water weight. You don’t want to see this in your garden.
  • The roots look like ginger roots – knobbly and hard to miss once you spot them.
  • It flowers between June and August with small white flowers.

If you already know that the property has Japanese knotweed on it, then ask your estate agent if they can get someone to visit the land to confirm this for you. If it is there, don’t buy or negotiate a price reduction on the property accordingly.

I hope you found this blog informative. If you are trying to sell your house, then contact me with all the details of your property and I will get back to you ASAP with some advice.

How do I get rid of Japanese Knotweed if it’s already in my garden

Japanese knotweed is a fast-growing plant in the buckwheat family. It can be a nuisance in gardens and natural areas, because of its ability to grow quickly and shade out other plants.

Japanese knotweed was brought over from Asia as an ornamental plant, but it has since become very common throughout the UK.

You may not notice that you have Japanese knotweed until the roots get deep enough into the ground to start growing up through your yard or garden; once this happens, it’s too late for treatment without professional help.

The good news is that there are steps you can take to control the spread of Japanese knotweed: keep it away from your garden or yard by keeping it cut back and mowed down, and avoid working the soil in an infested area because these plants can send out long, shallow roots that grow up to 30 feet away from the plant.

Another great option is to reach out to a professional contractor who has years of experience and the ‘know-how’ in o9rder to provide a successful treatment plan.

Want to know more about Japanese knotweed?

Knotweed Removal aims to provide the most up-to-date information, help and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.

Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.

The best means to contact us is via our email –

Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.

Knotweed Removal, UK

Bestseller No. 1
Bayer Garden 2 x Path, Patio & Drive Weed Killer & Watering Can Set - 3 x 8g Sachets per pack treats upto 75sqm - Kills Ground Elder, Nettles, Docks, Couch Grass & Japanese Knotweed.
  • This exclusive twin pack and 9L Watering Set is everything you need for clearing weeds from paths, patios and rives including areas of tarmac, concrete and block paving.
  • Kills tough weeds and their roots including: Ground Elder, Nettles, Docks, Couch Grass, Japanese Knotweed, Brambles, Bracken & Ivy.
  • Each box contains 3 x 8g Simple ready measured soluble doses and treats up to 75sqm. Apply at any time when weeds are showing green leaf and are actively growing.
  • Sold with our durable 9L or 2 gallon capacity galvanised steel watering can with removable brass rose. Colour cannot be guaranteed. Watering can will be randomly picked and despatched.
  • Keep children and pets away from treated areas until the spray has dried.
Bestseller No. 2
Roundup Tree Stump Weedkiller, Super Concentrate 250 ml
  • Kills ivy japanese knotweed, saplings, brambles and nettles to the root
  • Kills up to 16 tree stumps
  • Contains a reusable pipette for specialist treatment of japanese knotweed
  • Kills the roots so weeds don't come back
  • Degraded in the soil by micro organisms
Bestseller No. 3
Weedol 011005 Pathclear Weedkiller Liquid Concentrate, 6 + 2 Tubes
  • Unique dual action fomulation, kills weeds to the root and prevents new weeds growing for up to 3 months
  • Ideal for paths, drives and patios
  • No measuring or mess - just add water
  • Creates an invisible barrier that prevents new weeds for up to 3 months
  • Children and pets need not be excluded from treated areas (once dry)
Bestseller No. 4
RootBlast - RootBlast 360 Glyphosate Home Garden Weedkiller - 1L Bottle with Integral Measuring Device Pair - Includes Pair Of gloves - 1L Makes Up to 50L
  • WEED KILLER CONCENTRATE: Rootblast's strong weed killer is both super-concentrated and tough on most broad leaf and grass weeds. It's specifically designed to bring you the best results by using systematic herbicide technology. It targets weeds from the inside and kills them at their underlying roots, preventing any future growth
  • GLYPHOSATE WEED KILLER: For optimal weed control, Rootblast have created a concentrate weed killer that contains 360g/l of glyphosate. Glyphosate is a broad-spectrum systemic herbicide and crop desiccant that is used by famers. It kills and destroys the weed without affecting the crop. By using glyphosate, Rootblast's weed killer is stronger and more effective than most other weed killers on the market
  • GLYPHOSATE HERBICIDE: This powerful and effective weed killer is designed to target weeds such as dandelion, grasses, docks, nettles, willowherb, bindweed, woody brambles, tree stumps, ivy and more. After applying Rootblast's heavy duty weed killer, the first signs of weed control are visible when the weed leaves yellow - this can take anywhere from a few days to up to 2-4 weeks. From this 1 litre bottle of glyphosate herbicide concentrate, you can make up 50 litres of product when it's diluted
  • DOCK, GRASS & DANDELION KILLER: Alongside this industrial strength weed killer, you'll receive a pair of protective gloves as well as the integral measuring device attached to the bottle. The gloves provide you with protection to ensure your experience is as easy and safe as possible. The integral measuring device is an inbuilt measuring cup, simply remove cap and carefully squeeze the container until the cup is full
  • TOTAL PROTECT WEED GARDEN SPRAY: This easy to use product is available as a ready to use tough, concentrated weed killer that comes with a integral measuring device attached and protective gloves. Use by professional garden and farmers, this product can tackle your weed problem and kill the weed from the root - the ultimate weed killer!
Bestseller No. 5
Rootblast Glyphosate Weedkiller 4 x 100ml Concentrate with 5L Pump Sprayer
  • For use on unwanted vegetation and areas not intended to bear vegetation
  • Contains 72 g/l glyphosate for effective control of annual and deep-rooted perennial garden weeds, including grasses*, docks, nettles, willowherb, dandelion and bindweed. Also suitable for woody brambles, tree stumps and Ivy.
  • Coverage up to 66sqm per sachet

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