Japanese Knotweed – What are the dangers?

Japanese Knotweed might not be something which you have heard of before. For the people that don’t know, it is a pretty, red stemmed plant which has deep green leaves. It may look pretty but unfortunately it can cause you a lot of trouble. The reason it can cause a threat is because it grows so rapidly. Each plant can grow up to an inch a day and has the ability to mature rapidly across a large surface area.

So you are probably thinking “Why does this concern me?” Well, as it grows so quickly it can actually cause a lot of structural damage. It can cause damage to tarmac and concrete, increase erosion, damage retaining walls, damage building foundations and block drainage pipes.

How did it get here?

Japanese Knotweed was brought to Europe from Japan in the mid 19th century by Philipp von Siebold who discovered it growing on the sides of volcanoes.

Taking over Britain

As knotweed spreads extremely fast, it is surprising that it went undetected for years. According to researchers from the University of Leicestershire, people sharing cuttings of the weed and disposing of unwanted plants was the reason it spread so fast. Since then the plant has cost homeowners thousands of pounds in damage and a massive headache.

Identifying Japanese Knotweed

It is essential that it is caught in its early stages of growth. There are some recognisable characteristics which you should look out for:

• A hollow stem – almost like bamboo.
• Large spade shaped leaves.
• White flowers in the summer.
• In the autumn it dies leaving brown stems.
• Red tinged shoots when the plant first sprouts through the ground.

What can I do?

Unfortunately there are not many ways to stop the growth of Japanese Knotweed. You could try to dig it out but you should not leave any trace of it. It only takes 0.8g of root for a plant to grow again.

If you manage to dig it up, just be aware that knotweed is actually classified as controlled waste, under the Environmental Protection Act 1990, and can only be disposed of in licensed landfill sites.

Some chemicals can kill the knotweed, especially a chemical called glyphosate. It may kill it, but it can take up to 5 whole years for it to work.

Just remember

If you think you might have discovered Japanese Knotweed in your garden or anywhere on your property, you will either need to instruct a Surveyor or hire a specialist to assess the situation. Sometimes even cutting the stems can accelerate growth and cause it to spread – So just be aware!

You do have a duty of care if you discover this pesky plant on your property and you need to understand that removing Japanese Knotweed can be a long and expensive process.

If you wish to seek advice of a professional just call us on 0800 880 6024 or email us at office@rightsurveyors.co.uk

Alex Evans

You May Also Enjoy

Estate Agent Talk

Roller Garage Doors: 7 Essential Buying Tips.

Roller garage doors vary in quality, design, and the components used. Recognising these variations is essential when making a purchase, as it ensures you choose a product that provides long-term benefits. Here are seven key factors to consider: 1. Environmental Impact For superior insulation, sectional garage doors may be a better option, even though roller…
Read More
Breaking News

Glenigan Construction Index: Pockets of regional resilience, do little to offset faltering confidence

The value of underlying work starting on-site during the three months to February decreased 6% and remained 17% below 2024 levels as activity remains relatively stagnant Lowered expectations on economic recovery dent residential construction, with starts down 10% on the preceding three months, slashed by 14% against 2024 figures Non-residential project starts decreased 2% against…
Read More
Home and Living

How to Create a Stylish and Comfortable Home Office

Creating a stylish and comfortable home office is essential for productivity and well-being. Here are key considerations to design a workspace that is both functional and inspiring:​D 1. Select an Appropriate Location Choose a quiet area in your home with minimal distractions. If a separate room isn’t available, consider converting a nook or unused space…
Read More
Breaking News

Zoopla Rental Market Report: Rents rising at lowest level for 3.5 years

Upcoming reforms in the rental market will limit new investment and the number of homes for rent Rents rising at lowest level for 3.5 years as Zoopla warns upcoming rental reforms will continue to limit rental supply   Average UK rents for new lets are three per cent higher over the last year, down from…
Read More
Estate Agent Talk

Commonhold White Paper – Thoughts from the Industry

The sale of new leasehold flats in England and Wales is to be banned under Labour’s plan to end the  ‘feudal’ system. Labour wants to switch to Scotland’s commonhold system There are around 5 million leaseholders in England and Wales. Under commonhold, each flat owner would own the freehold of their home, but also have…
Read More
Breaking News

Greenpeace Ruling Exposes UK Government Policy

In January 2025, Greenpeace brought a collective action against the Dutch state for failing to comply with a 2018 European Court of Justice ruling on nutrient neutrality. An appeal is expected: however, as the UK Government has adopted the same ‘tax builders for pollution others cause’ approach to reducing nutrient pollution, it may find itself…
Read More