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Know your knotweed from your regular weeds

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Sat 29 Jul 2017

Know your knotweed from your regular weeds

Japanese knotweed deters nearly eight in 10 people in the UK from buying a property according to new research.

Having first been introduced to the UK from Japan in the 1850s as an ornamental plant, Japanese knotweed, or Fallopia Japonica, is now number one on the Environment Agency’s list of the UK’s most invasive plant species, described as ‘indisputably the UK’s most aggressive, destructive and invasive plant’.

According to the survey conducted by YouGov for removal specialist Environet UK, 78 per cent of those who were familiar with Japanese knotweed would be put off buying a property if they discovered the plant was present in the garden. 

Of those who would avoiding buying the property, 56 per cent cited the cost of removal as a deciding factor, 57 per cent thought that it would be too time consuming to deal with, and 69 per cent believed the weed could not be removed.

The report showed that whilst only four per cent of those aware of the weed had actually discovered it growing on their property, general awareness of the threat was high, with 75 per cent of those surveyed knowing about it. However, whilst many homeowners are conscious of its existence, there is still a high level of myth and misinformation around the threat posed by Japanese knotweed and the options available to those who discover it on their land.

Despite professional indemnity insurance now being available to protect against the risk posed by knotweed, only 3 per cent of respondents said they would proceed with the sale undeterred.

Nic Seal, managing director of Environet believes home owners are right to be concerned about the threat posed by Japanese knotweed, but that it doesn’t have to be a deal breaker. Knotweed can be dealt with swiftly when tackled by a professional, so there is hope for buyers who may have otherwise walked away from their dream home. 

How to identify Japanese knotweed

The appearance of knotweed changes dramatically through the seasons so it is important as an agent to know exactly what you are looking for at different times during the year.

In spring, red or purple asparagus type shoots will appear, quickly turning into green bamboo-like stems, which grow at a rapid rate. By early summer knotweed is usually fully grown; shooting up to three metres in height, it spreads rapidly and can push up through asphalt, cracks in concrete, driveways, cavity walls and drains in its quest for light and water.

The plant flowers in late summer, developing clusters of spiky stems covered in tiny creamy-white flowers. The leaves are luscious green in colour and usually flat and often shovel or heart shaped in appearance. In late autumn the leaves will fall and the canes turn dark brown. The plant then remains dormant during the winter months before sprouting back to life in Spring.

What you should be telling your customers

The presence of knotweed should be picked up during a site survey, however it is still important for agents to have a reasonable level of knowledge of the known issues and be aware of complications the weed can cause.

Homeowners are legally responsible for dealing with and preventing the spread of Japanese knotweed if it is discovered on their land. Failure to do so could incur a civil claims dispute resulting in receiving an ASBO if it spreads to a neighboring garden.

Whilst knotweed can now be completely removed within a matter of days, at any time during the year, financially, eradication can become costly if it is left untreated, so it is essential to have the plant dealt with by a professional as soon as possible to avoid further growth and prevent the sale of the property from falling through.