Why is Japanese Knotweed Bad?

Japanese knotweed is one of the most aggressive kinds of weed in the UK. In fact, it’s thought to be present in every 10 square kilometres of the country. Unless you know the effects that Japanese knotweed can have, this may not seem very alarming. Read on to get a good understanding of just why Japanese knotweed is such a problem.

Why is Japanese Knotweed Bad?

Japanese knotweed is ‘bad’ because it can cause extensive damage in the ground. Its roots are known to grow up to three metres down into the earth, and seven metres across. They can also develop to a thickness of around 20 centimetres if left to grow. These thick, strong roots will spread rapidly, letting almost nothing get in their way.

The Damage Caused by Japanese Knotweed

The spread of Japanese knotweed – particularly below ground rather than above, can cause severe damage. Not only to the growth of other plants, but also to manmade structures.

The problems caused by this weed are so bad that the UK has legislation in place to try to control its spread. According to Schedule 9 and Section 14 of the Wildlife and Countryside Act of 1981, it is:

“An offence to allow the plant to escape or cause it to grow in the wild. Whilst landowners are under no statutory obligation to remove Japanese knotweed from their property, where they are acting unreasonably and allowing it to cause a nuisance to the local community, local authorities and the police can now issue a Community Protection Notice against them to ensure that appropriate action is taken.”

What Can Japanese Knotweed Do?

The thick, rapidly spreading rhizomes (horizontal, underground stems) of Japanese knotweed are strong enough to damage a number of materials. Below are some of the problems that can be expected where the weed is present. It’s because of these that it’s important to act on Japanese knotweed as soon as it’s identified. Learn more about how to tell if you have Japanese knotweed.

Breakages and cracks to different materials

When they spread, the below-ground Japanese knotweed roots will find weak spots along their path, causing damage to:

• Slabs
• Concrete paths
• Brick walls
• Fence foundations
• Paving
• Driveways

They could push through whatever material lays in their path, which will ultimately cause unsightly damage. The owner of a site where Japanese knotweed grows will likely be met with costs for repairs and replacements, until it gets eradicated. These could be as little as simply replacing one garden slab, or as large as needing to excavate and repair building foundations.

Broken and blocked drainage

Japanese knotweed rhizomes are a known culprit for drainage issues. They can penetrate pipes below ground which could lead to a leak, which is particularly problematic for sewage pipes, especially if the weed is present in a communal area.

As well as this, they can cause blockages in piping, by breaking and continuing to grow through or inside a pipe. This too will cause issues for property owners, who will need to pay for plumbers to investigate the issue, plus replacement pipes.

Damage to underground cabling

In addition to damaging pipes, Japanese knotweed can also interrupt the flow of electricity if it grows around underground cabling. This could cause internet connectivity issues, or even full-on power cuts if the problem is allowed to get that bad.

Negative impact on the wildlife

As there is no known predator of Japanese knotweed in the UK, and it’s one of the most prevalent weeds we have, this plant can be significantly detrimental to other wildlife. If it’s present in areas of conservation, or local micro habitats, it can quickly take over and limit the potential of other species to thrive.

Is Japanese Knotweed Bad for House Sales?

Japanese knotweed presents issues for both current and future owners of a home, as well as neighbours on both sides. Knowing the problems that can be incurred, the presence of Japanese knotweed is a considerable downfall when it comes to selling a house. In fact, some mortgage lenders won’t release funds if it is determined that Japanese knotweed exists on the property.

If the owners of a property do not disclose the fact that this weed is present, it will often become apparent at the survey stage of a sale. At this point the owners will usually be asked to act on the problem and take steps for Japanese knotweed removal. Learn more about Japanese knotweed removal in residential settings.

How to Deal with Japanese Knotweed

Once it’s been determined that Japanese knotweed is present – and if you’re not sure, feel free to send us a photo and we will give you a no-obligation confirmation – you need to act fast.

While there are some DIY removal methods, unless every last trace of the plant is removed, you’re highly likely to experience regrowth and problems in the future. For this reason, it’s highly recommended that the experts are enlisted.

The team at Japanese Knotweed Specialists have extensive experience in this area, and we even offer Japanese knotweed guarantees for up to 35 years. This will usually cover the length of a mortgage, thereby satisfying lenders and allowing house sales to go ahead without undue complication. Get in touch for more information.