Japanese knotweed: the plant that destroys lives

The weed that destroys houses and ruins lives: Japanese knotweed


Japanese knotweed strikes fear into the heart of every homeowner. It looks innocuous enough as it lurks at the bottom of the garden, but left unchecked it can grow 10cm a day - destroying everything in its path. Just a few leaves in your garden are enough to slash the value of the property, and if it reaches your home, it can cause catastrophic damage.

The plant was brought to Britain by the Victorians who had no idea of its power. In Japan it was kept under control by insects and disease, but in the UK there has been nothing to stop it spreading. It means there's now no six mile area of the UK that is clear of Japanese knotweed, and if we tried to rid the county of the plant it would cost an estimated £1.25 billion.

We reveal five people whose properties have been blighted by the weed.

1. Destroyed
One of the most horrifying examples was back in 2011, when Matthew Jones and Sue Banks in Broxbourne, Hertfordshire were told they would have to knock their home down to get rid of a knotweed invasion.

The weed had spread into their garden and then made its way through the foundations and into the house. The sheer power of the plant means it can build up bulk behind concrete floors and foundations, forcing them to crack. Then it pushes through the cracks. The couple were told that the plant had done so much damage to their home that it was unstable. The value of the property fell from £305,000 to £50,000 - leaving them with no alternative but to knock it down and start again.

2. Halved in value
It doesn't have to hit your home for it to cause a headache: just being in the garden is enough. We reported in September that Elizabeth Abraham, a 91-year-old from Swansea, discovered that knotweed in her garden had destroyed more than half the value of her home.

She was moving into a care home and selling her property to cover the costs. However, the estate agent pointed out a huge knotweed growth in waste ground at the bottom of her garden, which had spread onto her plot. He said it cut the value of the house from £80,000 to £45,000.

3. Failed sale
In 2012 Peter Gingell was two weeks from exchanging contacts on the sale of his home when he had a call from his estate agent saying that the purchase had fallen through. The survey had found a 3cm high Japanese knotweed plant in the back garden, and the mortgage company wouldn't lend on the property. He called in a specialist who said it could be eradicated in two years, but by then Gingell had spent his savings on a failed house move, and was left with an unmortgageable flat.

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4. Failed sale number 2
In 2012 Karen Platt from Crookes in Sheffield lost a sale on her house when a valuer found knotweed had spread into her garden. The following year her estate agent told he she would have to take the property off the market, and have the plant treated and eradicated (with a guarantee from a specialist firm) before she could sell the house. Ironically she wanted to sell in order to move into a smaller property without a garden - as ill-health made it hard for her to do work around the house.

5. Disaster from next door
It doesn't have to be in your garden either - having the weed on a neighbouring property is enough to cause you problems. Last year Ben Metcalf, a 35-year-old father from Stockport, thought he'd finally found a buyer for his home, after two years of trying to sell it. Unfortunately a surveyor told him there was knotweed on council land behind his home, wiping £20,000 off the £100,000 value of his property.

What can you do?
The stories are terrifying, but it's important to remember that if you have the plant in your garden, it doesn't have to be the end of the world. Some mortgage companies are less draconian than others, so if you have the plant treated and go to a specialist broker you should be able to secure a deal.

You will need to get it treated quickly. Weedkiller can be injected into the roots, and it can be regularly cut back to stop it advancing while it is dying off. It'll need to be treated twice a year for three years to get it under control, and because it is classed as controlled waste, you need a specialist to do this for you. It will easily cost £1,500 over this time, but it can be brought under control and you will be able to move on.

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