Can Japanese knotweed damage property

Japanese knotweed damage is becoming more and more of a concern with property and landowners alike. Its invasive nature can cause damage to pipes, sewers, roads, foundations, walls, paths and drives.

Japanese knotweed can grow up to 10 feet per month and it’s virtually impossible to get rid of once it takes hold.

If you have Japanese knotweed on your property, you need to take action immediately. Call an experienced professional to remove the weed before it causes any more damage.

Is Japanese knotweed as bad as the media say it is?

There is no question that Japanese knotweed harms the environment. While some people overreact to the issue, others fail to give it the attention it deserves.

It is fair to claim that media outlets have in the past sensationalised extreme incidents of damage to make a good story and even to frighten people into believing that their homes are about to be attacked by this invasive menace.

Japanese knotweed has a well-deserved reputation as one of the most aggressive plants in the UK because, despite doing comparable quantities of damage to other troublesome species like bamboo or buddleia, it is sadly much more difficult to eradicate.

Of course, Japanese knotweed also has legal and environmental repercussions, so destruction isn’t the only issue to be concerned about.

Japanese knotweed can damage patios and driveways
Japanese knotweed can damage buildings and their foundations
Growing on borders it soon encroaches into neighbouring properties

Is there evidence of Japanese knotweed causing damage?

Over the past 25 years, specialists in the UK have compiled a significant body of information showing the harm that Japanese knotweed has done.

The media’s natural propensity is to exaggerate the worst-case scenario, hence the actual severity of the harm caused by Japanese knotweed is frequently exaggerated. But that doesn’t mean it should be disregarded.

Newspaper articles have claimed that a building needed to be torn down because knotweed was growing below it. Although it is obvious that this is untrue, it is equally untrue to claim that Japanese knotweed does not seriously harm structures. The reality, as always, lies somewhere in the middle of these two extremes.

A limited study published in 2018 called “Japanese knotweed (Fallopia japonica): An analysis of capacity to cause structural damage (compared to other plants) and typical rhizome extension” concluded that;

(Japanese knotweed) should not be considered any more of a risk, with respect to capacity to cause structural damage in urban environments, than a range of other species of plant, and less so than many.

2018 study by the NCBI
Japanese knotweed growing wild and free on a property and causing damage to any physical structure in its way
Japanese knotweed growing wild and free on a property and causing damage to any physical structure in its way
*image courtesy of visualhunt.com

How does Japanese knotweed cause damage?

Japanese knotweed is unlikely to directly collapse or cause substantial structural damage to buildings. However, Japanese knotweed can harm nearby walls and fences because of its above-ground canopy, as well as due to its increasing network of underground rhizomes and roots, as well as its crown in mature stands.

Rhizomes that creep and are highly regenerative can take advantage of cracks in built structures, and as they grow over time, they put pressure on the element to harm it. The general rule of thumb is that knotweed can invade if water can.

the roots of Japanese knotweed damage pipes and sewers
Borders and walls can crumble from the growth of Japanese knotweed

What type of damage is caused by Japanese knotweed?

Japanese knotweed is an invasive plant that can do a lot of damage. It can grow up to twelve feet tall and it spreads rapidly, choking out other plants.

Japanese knotweed also damages buildings and infrastructure, costing homeowners and landowners millions every year.

If left unchecked, the damage could progress from cosmetic to substantial, which would be expensive to fix. Damage examples include;

  • Complete obstructing of downpipes, drains and sewers
  • Destruction of surfaces made of resin and asphalt
  • Stone and brick walls falling down
  • Cracks and fissures in the hollow walls
  • Intrusion through expansion joints and internal building growth
  • Undermining and raising patios and driveways
  • Fence and boundary walls falling down
  • Structural integrity issues, including dampness
  • Obstruction of air vents, ducts, and chimneys
Japanese knotweed invading a neighbours property
Japanese knotweed causing damage to a neighbours fence
Japanese knotweed consumes a garden and kills any native plants
Damage to land and gardens from the invasive growth of Japanese knotweed

What can Japanese knotweed do to a property?

Japanese knotweed is an issue since it is particularly good at identifying structural flaws and taking advantage of any cracks or fissures within a property. It can force its way through drains, cavity walls, and other weak spots like cracks and fissures.

However, this type of damage is uncommon and would only happen in cases where the issue had been disregarded for a substantial amount of time.

Japanese knotweed can inflict greater harm when it spreads inside of infrastructure, deepening cracks and wreaking havoc as it goes. It is essential that you take action right away if you discover Japanese knotweed in your garden.

You must disclose the presence of Japanese knotweed on your property when selling. Additionally, you have a responsibility to stop it from contaminating nearby property or the wild.

The aggressive growth of Japanese knotweed next to a neighbour's fence
The aggressive growth of Japanese knotweed next to a neighbour’s fence

Can Japanese knotweed grow through Concrete?

The short answer is no. Japanese knotweed cannot grow through concrete. It can break concrete apart but only if there is a pre-existing crack or fissure. 

When people see Japanese knotweed for the first time on their land, they frequently feel panicked and make an effort to remove it. One of the myths about this invasive weed that we frequently see is that it can grow through concrete, however, this is a myth.

Japanese knotweed is a very invasive, rapidly growing plant that can cause serious damage, which is why it is crucial to eradicating it as soon as possible.

Although no plant can truly pass through solid concrete, it will look for cracks to eventually try to do so. The surrounding concrete may be forced apart as the plant grows larger and does more harm. If a concrete surface is solid and free from fissures and cracks, you should anticipate Japanese knotweed to keep away from it.

Further research is being undertaken by Swansea University scientists to find better ways to manage and control this invasive weed with their intensive five year study.

Swansea University

In conclusion

Does Japanese Knotweed Damage Property?

Japanese knotweed is a highly invasive weed that can damage property if left unchecked. The plant grows rapidly and spreads quickly, forming dense colonies that can cause structural damage to homes and other buildings. In addition, Japanese knotweed produces large quantities of seeds which can spread the weed to new areas.

If you think you may have Japanese knotweed on your property, it is important to take action to remove it as soon as possible. Contact a professional landscaping company for assistance in removing this weed and preventing any further damage.

Want to know more about Japanese knotweed?

Knotweed Removal aims to provide the most up-to-date information, help, and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.

Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.

The best means to contact us is via our email – hello@knotweedremoval.tips

Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides, and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.

Knotweed Removal, UK

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