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Japanese Knotweed - The plant that could cost you your home!

If, like me, you are not particularly green-fingered, you might think that one plant looks pretty much like another. In which case you are in danger of missing a silent assassin gaining strength within your garden.

Japanese knotweed looks like lots of other weeds, but it has the power to ruin your home and cost you thousands of pounds. There have been reported cases of the weed slashing house prices by half and on extreme levels reports of houses having to be demolished in order to treat the scourge of Japanese knotweed that had penetrated through walls. These are clearly extreme examples but Japanese knotweed is almost always a problem for homeowners (and potentially their neighbours).

So what exactly is Japanese knotweed?

Japanese knotweed has been in the UK since the 1800s, having been introduced as an ornamental plant by the Victorians.
It looks pretty innocuous, like many plants or weeds, and is described by the Environment Agency as lush green in colour with shovel shaped leaves and a stem that looks like bamboo. It also produces white flowers in autumn and grows rapidly, up to 10cm a day. It spreads like wildfire through its stems underground, growing a metre in a month and potentially causing heave below buildings.

Once the concrete or tarmac cracks from the heave, the plant has a way into your home, working its way through the tiny gaps and potentially causing structural damage or blocking drains. It is the most invasive plant in the UK and very persistent indeed.

What to do about it?

Whatever you do, do not ignore it. Japanese knotweed grows rapidly and if it infects your neighbours’ gardens and properties, whilst not an offence to have knotweed in a garden, the Anti-Social Behaviour, Crime and Policing Act can be used to compel land owners to remove Japanese Knotweed where its presence is causing nuisance or damage to neighbouring property. This is achieved through the issue of a Community Protection Notice by the Police or, more commonly, the Local Authority.

Breaching the terms of such a notice is a criminal offence subject to a fixed penalty notice or prosecution.
You will therefore need to focus on stopping the plant spreading and getting rid of it. Treatments usually include a combination of herbicide treatment and excavation. Under the Environmental Agency’s code of practice there are a lot of hoops to jump through to get rid of this plant properly and that’s why many people pay a specialist contractor to ensure the job is done properly.

But what should you do if you notice this plant and you are about to sell your home? Sellers are now obliged to confirm the presence of knotweed, where it is within their knowledge, via the Law Society’s Property Information Form. Nevertheless it is important that a prospective purchaser make their own inspection, and instruct their own professional survey, as the potential repercussions of finding Knotweed on your land can be serious.

If you are trying to sell your home and you discover Japanese knotweed in your garden, it is therefore likely to cause you problems. Some buyers will not touch a house if they know this plant is in the garden, or even neighbouring gardens. And even those that are willing to deal with it may find their mortgage lender will not offer them a loan once they learn of it, because of its potential to cause damage.

But it’s not all bad news. According to the Council of Mortgage Lenders many lenders will now consider lending on a property with Japanese knotweed (and they expect their surveyor to spot it during the valuation). They usually consider applications on a case-by-case basis and look for evidence of an initial treatment, with a commitment to an ongoing treatment programme.

You may also be able to take out indemnity insurance against this epidemic– this covers the owner and any mortgage company involved and provides a £20,000.00 level of indemnity so, if Japanese Knotweed appears within 5 years, surveys and/or remediation costs, repair works and legal fees and loss of market value are covered. There are however strict criteria that will need to be met in order for you to make a claim.

Japanese knotweed can be a major problem for homeowners but it can also be dealt with if caught early and treated effectively by an experienced contractor. If you have the weed in your garden, tackle it head on because, one thing is certain, it won’t go away without a fight!

If you would like further information or to find out how we can assist you, call 01484 915 000 or email Seema Gabbi.

About the Author

Seema Gabbi


Seema Gabbi has over 14 years of experience in both residential and commercial Conveyancing. 


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