Are house buyers put off by Japanese Knotweed?
Japanese knotweed can cause huge amounts of damage to a house and will put any buyer off.

Two words that will inject a state of fear into any homeowner or buyer are Japanese Knotweed. But is this legendary concrete-smashing, tarmac-raising plant really as concerning as people say?

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The short answer is potentially. If a surveyor discovers Japanese Knotweed, also known as Fallopia Japonica, on the premises, it may well put your buyers off. In addition, some mortgage providers will not approve borrowing against a property with Japanese Knotweed or will want a guarantee of an effective treatment programme. Presence of the non-native plant can also threaten to wipe thousands off your asking price- 850,000 houses in the UK suffered from a 10% reduction of value due to Japanese Knotweed.

It’s not a complete disaster if you find some though. Let’s take a look at the facts so you can plan what to do about Japanese Knotweed.

• The distinctive bamboo-like plant is listed by the World Conservation Union as one of the world’s worst invasive species.
• Its root system and strong growth can, in extreme cases, damage concrete foundations, drainage systems and walls, as well as strangle other plants.
• It has a large underground network of roots (rhizomes) which need to be killed to destroy the plant. It can take three years of regular herbicide treatment to render it ‘dormant’.
• You don’t have to remove or control it by law, but you could be prosecuted for causing a nuisance if Japanese Knotweed in your garden spreads to neighbouring properties.
• It’s a criminal offence to plant it or cause it to grow in the wild – for example, by not disposing of plant or soil waste properly. You could be fined or go to prison for up to two years.

All in all, this graceful, innocent-looking plant isn’t something the unsuspecting homeowner or gardener wants responsibility for.

How to get rid of Japanese Knotweed

1. Start as soon as possible.

2. If you need to sell your house fast, home buyers and mortgage providers might be happy to go ahead with buying your house if they have a guarantee that the situation is being handled by experts, so you might try an approved specialist like Environet or TP Knotweed Solutions to ensure the situation is controlled and handled correctly.

3. Picking the right herbicide is essential, as it must travel through the plant and into the root system below. If you’re planning to battle the plant yourself, use a total weedkiller, such as glyphosate.

4. Cut old stems in winter and spray the plant in late summer when the weed is flowering. You’ll need to re-apply in midsummer, evaluate in September, and spray again if needed. Then check again the following spring; even after all that, it can take a few seasons to eradicate using glyphosate.

5. Never ever put any cut stems or roots into green waste bins or domestic bins – the 1981 Wildlife and Countryside Act made it illegal to plant Japanese knotweed in the wild or to allow it to grow by careless disposal. It’s much safer to take the cuttings to a licensed waste site.

How do I know how serious my case is?

As long as you’ve identified the plant before it has managed to cause damage, it will take a bit of money and effort but your property will be okay. Our advice would be to remain pragmatic, and seek out the help and advice you need. If you’re looking to sell your property, contact We Buy Any House for a free quote, or alternatively for more tips about selling your house, see our recent article detailing the ways you can speed up your conveyancing. You can also check this planttracker created by the Environment Agency which tracks the plant, and shows over 6,000 locations in the UK and see if your area might be at risk.

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