What is Japanese Knotweed?

Many consider Japanese knotweed is an invasive weed. It is also known as Fallopia japonica. It has bamboo-like stems and creeping roots, which can quickly occupy space. Digging out the roots is very difficult since its roots can grow up to 1m deep. Japanese knotweed grows through cracks in pipework and brickwork. It is illegal to allow the plant to spread onto the land of other people or into the wild. Therefore if you identify this weed it is your responsibility to kill Japanese knotweed to prevent its return. 

How Can I Identify Japanese Knotweed?

Japanese knotweed is an herbaceous perennial weed. It usually grows in huge clumps of bamboo-like canes. The canes can grow up to 2.1 meters high and have purple spots. The stems alternate from these. The leaves are heart-shaped and light green and the flowers are creamy-white. The length of the leaves is 14 cm and the length of the flowers is 15 cm. Japanese knotweed becomes dormant from late autumn. Also, the canes die, losing their leaves. Once the canes die, they remain standing. It can even take years for the canes to decompose. 

Fleshy shoots, which are reddish, grow on their own in spring. The shoots may even grow on the dead canes. Therefore, new canes, flowers, and leaves can grow from the shoots. 

It is easy to confuse Japanese knotweed with other plants, such as the Russian vine. The leaf shape and flowers of the Russian vine are the same as those of Japanese knotweed. Unlike the leaves of Japanese knotweed, the leaves of Russian vine are arrow-shaped and have a scrambling habit. It is easy to identify them due to the lack of tall stems. 

It is also easy to confuse Japanese knotweed with Himalayan honeysuckle. If you inspect the two closely, you will find that the leaves of Himalayan honeysuckle are opposite. Therefore, the Himalayan honeysuckle does not have alternate leaves. It also has different long, white, and purple flowers. The shape of the leaves of some persicaria species is similar. However, they are narrow and the growth is not bamboo-like. 

How Does Japanese Knotweed Cause Problems?

The plant can grow from tiny parts of the root. It is easy for the plant to spread across your property and into other properties since it is vigorous. The roots of this plant can exploit the cracks in pipework and brickwork. The roots can damage your road. If Japanese knotweed grows near your home, do not hesitate to get rid of it. This is because the plant can damage your home’s foundations. Contact the experts at Environet.

The plant can also grow from seed. Therefore, if the plant grows in your neighbor’s garden, it is more likely to spread to your garden. It spreads by its seed or spreading roots. It is, therefore, necessary to look for early signs of Japanese knotweed growth to help you stop the plant from spreading into your garden. 

The plant can cause more problems in your garden because of its invasive nature. It can even out-compete the plants growing in your garden. The plant can also cause more problems in the wild. Unfortunately, it is easy for Japanese knotweed to grow and spread in the wild, spreading and threatening the natural ecosystems. You will mostly see Japanese knotweed along canal towpaths, at train stations, and along railway banks. The wind from the passing traffic makes it easy for the seed of the Japanese knotweed to spread. 

Japanese Knotweed and the Law

According to the Wildlife and Countryside Act 1981, it is illegal to grow Japanese knotweed in the wild. Therefore, you cannot allow the plant to escape your garden and grow in the wild. 

However, the law allows you to grow the plant in your garden. However, it is not legal to allow the plant to spread into your neighbor’s garden or into the wild. Therefore, it is essential to learn how to eradicate the plant or control the spread of the plant. If you want to sell your property, you must remove the plant before you sell it. Since 2013, sellers must check their gardens for Japanese knotweed and declare the presence of the plant and provide details of eradicating or managing the plant. 

If you want to buy a property and you found out there is Japanese knotweed on the property, you may need to provide a management plan for the eradication of the plant to your mortgage lender. Get in touch with Environet to work out a plan of action.

According to the Environmental Protection Act 1990, the plant was classified as ‘controlled waste’. Therefore, it is not legal to add the plant to council-run or home-compost garden waste bins. The law permits you to burn the waste. However, you need to let it dry first. Alternatively, you can dispose of the plant at a licensed landfill site. 

If someone dumps the plant in the wild, do not hesitate to get in touch with The Environment Agency. 

How Do You Remove Japanese Knotweed?

It is easy to manage small clumps of the plant. You can dig out or spray the plant with a weedkiller to remove it from your property. However, it is much better to hire a professional service like Environet to completely remove large clumps of the plant. It is beneficial to hire professionals since they write risk reports and provide treatment plans. Mortgage lenders accept the treatment plans of the professionals since they have a guarantee.  

Organic Methods on How to Remove Japanese Knotweed

Do not dig out the plant since it can cause problems in the future. This is because the plant can regenerate from pieces of its roots. Remove the leaves as they grow to gradually weaken Japanese knotweed. Removing the leaves stops photosynthesis. However, it can take many years to completely eradicate the plant using this method. Therefore, you will need to check the Japanese knotweed every week and remove any new leaf buds. It is even better to remove the leaves immediately you see them. 

Chemical Controls Used to Remove Japanese Knotweed

One of the best options is the glyphosate-based weedkiller. However, you will need to apply it for around four seasons to completely get rid of the plant on your property. It is best to cut the canes before you apply the weedkiller to allow the weedkiller to penetrate the roots and the plant. Different brands have different instructions. So, check the instructions of your weedkiller before using it. Speak to Environet for more information.

It is better to follow the instructions of the manufacturer to make sure the weedkiller eradicates the problem and minimizes risks to yourself, loved ones, pets, and even wildlife. 

If you use glyphosate-based weedkiller to control the plant, the plant may regrow in the following spring. Fortunately, the plant will be less vigorous. Therefore, you will need to administer the glyphosate-based weedkiller on the new growth.