What is Japanese knotweed?
Japanese knotweed is a menace. This fast-growing and hardy perennial is incredibly tough to remove and can quickly decimate a property’s value.
Knotweed can also rapidly spread onto neighbouring land and properties, frequently making its way onto a property from untended surrounding areas like railway grounds, shopping centres, canals, and rivers.
This can see landowners, from where the knotweed has originated, paying thousands in removal fees and compensation as it is illegal to allow the spread of Japanese knotweed.
If you believe knotweed is growing on your property it is essential you have it identified and removed as quickly and effectively as possible. If not treated correctly it can and will grow back, causing further issues.
When it comes to identification, Japanese knotweed looks very different depending on the season, so it’s important to know what to look for.
How to remove Japanese knotweed
On top of devaluing properties by around 5%, the presence of Japanese knotweed can make it extremely difficult to sell, with mortgage providers refusing to allow a sale unless the growth is removed. If knotweed is present but not disclosed on a property that you sell (even if you believed the plant was eradicated) you could be held liable and be forced to pay for the removal of the weed on the claimant’s land in addition to compensation for damages.
While ill-advised, you can attempt to remove Japanese knotweed yourself, however, using a professional company will give you an insurance-backed guarantee, meaning that you are covered if the plant returns. DIY attempts are often more likely to cause additional harm or spread the weed further.
Treatment methods include the use of glyphosate-based herbicides to kill knotweed before excavating the root-systems, and a comparatively new system using electricity to destroy the plant from the inside.
While professional Japanese knotweed companies can be expensive, it is much better, in the long run, to act quickly to remove the invasive species using qualified specialists, rather than letting it continue to grow unimpeded and risking additional complications (including being held liable for damages to neighbouring property) down the line.
In many instances, you will be able to bring a case against the party at fault for allowing the knotweed to grow and encroach onto your land. The cost for the removal can be awarded alongside compensation from the defendant following a successful claim, meaning you will not need to pay for the specialists yourself if your case is successful.
Removing the plant yourself
Attempting to treat Japanese knotweed without expert help is discouraged by the UK government. This is because it is exceedingly difficult to remove all traces of Japanese knotweed. The plant can and will grow back if even tiny pieces of root remain. The disposal of the weed, once it has been removed, is also highly controlled and requires extensive understanding and time to do so legally.
Unofficial “remedies” include the use of diesel, bleach, and burning, and are at best ineffective and discouraged by the UK government, and at worst, illegal. Many are hazardous not only to the soil but also to local flora, fauna and humans. Additionally, some mistakenly believe you can kill Japanese knotweed by shredding the plant with a lawnmower. This, however, will only work to further spread the weed, exacerbating the issue and likely resulting in neighbouring properties being able to make a claim against you for illegally spreading the plant.
Disposing of knotweed
Treating Japanese knotweed alone is not enough. The weed must be removed from your property to ensure that it cannot grow back. The roots of Japanese knotweed grow to 3 metres in depth, which makes it incredibly difficult to fully eliminate. Any remaining pieces of root (also known as rhizome) will regrow, and before long the infestation will return. Japanese knotweed has been shown to grow from as little as 0.2g of remaining root. That’s a piece of rhizome equivalent in weight to 1/5th of a paperclip or a single drop of water!
Once the Japanese knotweed on your property has been exterminated you then need to figure out how you will exhume and then dispose of it. Professional Japanese knotweed services will be able to handle this for you. Attempting to remove the plant yourself is exceedingly time-consuming and difficult and involves contacting the Environment Agency, obtaining permits, using dedicated equipment and adhering to very strict regulations. Again, you will also need to ensure that even tiny fragments of rhizome are completely removed or risk the infestation returning.
What to do if you have Japanese Knotweed
You must act quickly once you suspect Japanese knotweed is growing on your property to reduce the cost of removal and ensure that you cannot be held liable for allowing it to spread.
Mark Montaldo, a director at CEL Solicitors and Japanese knotweed expert said:
“Japanese knotweed is an aggressive weed that grows incredibly quickly and can be found all over the country. Removing knotweed should be a priority for anybody who discovers the plant on their property. While it isn’t illegal to have Japanese knotweed on your land, it is illegal to allow it to spread. If it is on your land, you may be able to claim for the cost of removal from the party at fault, whether that’s the owners of neighbouring land who allowed it to encroach on your property, or the previous owner/surveyor who failed to disclose its presence.
Working with trained specialists is essential to making sure that the plant is totally removed from a property and that it will not grow back. Trying to remove knotweed without expert help more often results in the problem spreading and getting worse, which makes it more difficult and expensive to get rid of in the long run.”
Your ability to bring a Japanese knotweed claim depends on your situation, including whether the weed spread from neighbouring land or was present when you purchased your property. In both events, you may be able to claim for the cost of removal, plus additional compensation. This will also give you an insurance-backed guarantee against the weed returning.