The question of whether you should buy a house with Japanese knotweed in the garden is the main concern these days due to it potentially devaluing the property.

Removing Japanese knotweed permanently can be a troublesome exercise which, if not carried out properly, can be an action in futility since this invasive ornamental plant has a ‘never die attitude’ that stimulates its quick growth where no permanent removal has been successful.

Japanese knotweed can have disastrous consequences to property, the environment and the structural integrity of buildings if one does not get rid of it at the earliest possible stage.

The tenacious root system of this highly invasive weed plant can cause havoc even to the strongest of structures. Based on the foregoing, it is clear that having Japanese knotweed in the garden is a disaster waiting to happen.

Here are some reasons why you should avoid buying a house with Japanese knotweed;

Damage to the environment

The presence of Japanese knotweed in your garden poses a bigger threat to the surrounding environment that you live in. 

For instance, this weed plant’s ability to grow up to 12 feet tall implies that it can dominate the vegetation beneath and deprive it of sunlight thus impeding further growth and in extreme circumstances leading to extinction.

The beautiful environment that you enjoy will no longer be there, just an invasive weed plant. This factor should make you despise the presence of Japanese knotweed in your garden.

Condenses play area

Japanese knotweed does not stop growing and spreading. The roots of this weed plant can grow up to 3 metres into the soil and spread up to 7 metres wide.

Taking into account that it is this tenacious root system that supports the whole plant and its growth, this should be a big cause for concern the moment you spot the weed growing in your garden.

As each day passes, this weed plant continues to spread within the garden and the end result as a consequence will be to significantly reduce the size of your garden/play area.

To this end, you, the children and any domestic animals that you may no longer enjoy the serenity of the garden area. This is why you should think twice before buying any house with Japanese knotweed in the garden.

Japanese knotweed can spread beyond gardens to all other areas within our community
Japanese knotweed can spread beyond gardens to all other areas within our community

Boundary fences

It is a common practice to find homeowners erecting fences around their property.

Such fences/boundaries most times are made of wooden or plant material that is meant to act as beautification hence may not be very strong to withstand heavy force because this is exactly what the weed plant brings when it comes into contact with such fences.

Considering that the Japanese knotweed, once fully grown especially from the ground up, can become very heavy, it can easily overwhelm lightweight garden walls and fences, especially where the foundations are not so strong or poorly constructed.

You should be wary of this element because if you do not get rid of the Japanese knotweed in your garden, then you must be vigilant in conducting repairs within the property where necessary in the event that the weed plant causes damage.

Interior Damage

If you think Japanese knotweed cannot attack the interior of your house, you are wrong. Japanese knotweed does not discriminate on its preferred location of growth, this poses a greater problem to homeowners of the possibility to deal with the weed plant once it starts creeping through the tiny cracks and occupying the inside of the house.

The weed plant can ascent up the house walls, making the interior unpleasant and uninhabitable if not dealt with urgently.

Basically, this weed plant can go to the extent of scrubbing off the paint on your walls, creeping under your household’s items and making life a living hell.

For that reason, buying a house with Japanese knotweed should be a no for any person intending to have peace and quiet enjoying the property space.

Damage to walls and property is inevitable if left unattended
Damage to walls and property is inevitable if left unattended

Weakening house structures

Often, you can find small cracks between the joints of a house, especially at the doors or windows. Japanese knotweed has a tendency to creep through the walls of buildings mainly in search of sufficient sunlight as this is one of the components that it requires to constantly grow.

This genetic behaviour makes the weed plant extremely harmful because it will exploit the tiny cracks, especially those that are near the joints of doors and windows and forcefully penetrate through.

If this problem is not dealt with at the earliest possible time, it may eventually result in the widening of such cracks and the end result is that you may need to do repairs.


From the onset, the presence of Japanese knotweed in the garden should be a red flag that you should not ignore before buying a house. As a matter of fact, you should refrain from buying such a house at all costs for our own best interests.

Recent studies show that the presence of Japanese knotweed in an area causes the value of the property in that area to depreciate depreciates based on the invasive nature of the weed and the unprecedented damage that is likely to result.

Additionally, very few people will invest in a property that does not guarantee good serenity, peace, and quiet free of an invasive weed such as the Japanese knotweed.

Taking into account that Japanese knotweed is dangerous to the environment and buildings; this aspect greatly contributes to the depreciation of property investments around an area affected by the weed.

Additionally, there are many emerging cases of mortgage lenders being overly reluctant to offer financial support to purchasers intending to buy such properties under the Japanese knotweed attack.

The invasive nature of the Japanese knotweed makes it lethal once it is allowed to overstay in any location.

Before you buy a house with Japanese knotweed in the garden, it will be wise if you first worked out a plan on how to get rid of the weed plant with the seller of such a house before ownership is transferred to you.

Can Japanese knotweed grow through concrete? - knotweed removal
Can Japanese knotweed grow through concrete? – knotweed removal

Want to know more about Japanese knotweed in the garden?

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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