What kills Japanese Knotweed permanently? We look at what methods kill Japanese Knotweed and which ones do not. Find out more about killing Japanese Knotweed.

How do I permanently get rid of Japanese Knotweed?

Tackling Japanese Knotweed is challenging, with it being one of the most invasive plants on the planet. Considered controlled waste, with specific removal methods used to eradicate Japanese Knotweed, getting rid of it permanently can be tough. To completely eradicate Japanese Knotweed, there are some things you can do. 

• Correctly identify it. Knotweed is sometimes confused with Giant Hogweed, which is dangerous for different reasons. The sooner you can identify Japanese Knotweed, the sooner you are likely to remove it.
• Cut canes to the ground. Cutting Japanese Knotweed is not an easy task and, when done incorrectly, can cause further spread of the plant. For this, you can be fined. Take great care when cutting down the bamboo-like canes, and remove them from your soil immediately afterwards.
• Use a Glyphosate-based weed killer. To kill Japanese Knotweed, only apply the weed killer to the cut canes and avoid contact with other plants, as they will suffer. 

From there, you should be cutting the plants weekly, ensuring you do not leave any stems lying on the grass. Killing Japanese Knotweed takes time and precision, as the weed killer will not destroy them in one. You should also give the herbicide time to work, as applying too much will not achieve results.

If the plants continue to irritate, we advise you to contact professional help as soon as possible, and they can provide services or information on glyphosate-based weedkillers. Identifying the weed is essential because Knotweed is commonly confused with Russian vines and Himalayan honeysuckles, both of which present their own set of issues. 

Do These Methods Kill Japanese Knotweed?

The reason why it's so hard to remove Japanese Knotweed is because of the plant's rhizomes (roots) which work underground to spread quickly. Invasive non-native plants like Japanese Knotweed grows between 10-20cm per day because of the roots burrowing deep and wide from the visible plant.

How Do I Permanently Get Rid Of Knotweed?

Many websites will tell you the best method for Japanese Knotweed eradication is herbicide application, but this is not a long-lasting method and will not completely eradicate the invasive weed. 

Herbicide Treatment Programs (HTP) are effective in limiting Japanese Knotweed growth, but herbicide treatments cannot remove the rhizomes from the ground - which is crucial in controlling the weed.

Here are some common eradication methods you will find online, and if they really work. 

Regardless of what chemical controls you choose, you should apply them sparingly so as not to damage the surrounding areas. Wildlife and plants around you may be protected, and you should prioritise nature's health around the weed.

Due to the alkaline qualities, some homeowners have used lime as a natural remedy for removing Knotweed. This can neutralise acidity levels in the soil but can be dangerous for humans and animals on skin contact. Minimising risks to yourself and the plant's further growth should be your main priority. 

What is the problem with Japanese Knotweed?

Japanese Knotweed (fallopia japonica or polygonum cuspidatum) is one of the UK's worst invasive weeds, taking over entire areas with underground roots and spreading incredibly quickly throughout early Summer. 

It is extremely difficult to remove this non-native weed as it can span neighbouring properties, and most other methods used against weeds are futile.

The weed will bloom creamy-white flowers throughout late Summer and continue growth throughout Autumn, seeming to die out in the following Spring. This is a facade, and the roots are still alive underground for this cycle to repeat. The rhizomes can spread over 2 metres from the visible plant, meaning you can have a bigger problem on your hands than seen.

Knotweed was introduced to the UK as an ornamental garden plant, with the female being the only thing to be introduced. Due to this, the weed cannot seed as other plants do, relying on the roots and human disruption to spread further. Fly-tipping is the main contributor to Japanese Knotweed as the shoots can spread throughout ground-level disturbance.

While Knotweed is not poisonous or harmful to humans or pets, it can cause severe structural damage to property foundations and riverbeds, causing flooding and expensive fixes. Livestock can eat this plant, but this is not a permanent solution to removing the weed. 

Buying And Selling Property Where Japanese Knotweed Is Present 

There are, of course, complications with buying and selling property where Knotweed is found. All sellers must inform future buyers and estate agents when Knotweed is on their property, which is done through a TA6 form. Solicitors and Conveyancers can provide more legal advice and information, but you are required to make the presence of this weed apparent.

Some mortgage lenders will refuse a property outright when they know Knotweed is on the site, so you must provide information about it when selling. 

A TA6 form outlines your management plan for eradication and which trade body or professional company you're using to remove it safely from the site. Always look for someone accredited with the property care association (PCA) and with experience in removing invasive weeds.

While it is not illegal to have the weed on your property (as outlined in the Anti-social Behaviour, Crime and Policing Act 2014), you should be taking care to manage it so as not to spread it further. If you aid the spread of such a weed, you can be fined £2000 and spend up to 2 years in prison. 

This should be taken into account if you plan to sell your house in the near future. If your neighbour is threatening litigation against you for spreading the weed, you must defend yourself and leave it to the professionals.

While dealing with this weed is time-consuming, you should not leave it unattended as it will only worsen. Few other weeds can lay dormant over several seasons, but Japanese Knotweed can sprout when you're least expecting it and cause high disposal costs. 

By using a professional company such as our own, you receive insurance-backed guarantees we will remove it safely from your site, only performing work we deem safe. Please get in touch if you are suffering from an invasive weed issue at your residential property.