Japanese Knotweed, a perennial plant native to East Asia, with attractive, bamboo-like stems and shield-like leaves, can be found all over the UK. The plant comes with a fearsome reputation; however, it is often confused with other plants, which has led to people believing that it is dangerous to human health.

Can Japanese knotweed be harmful to human health? 

Japanese Knotweed is not poisonous, meaning it can be safely handled and picked. It does not cause burns or skin irritation. This makes Japanese Knotweed a benign plant in terms of direct harm to humans or animals. 

In fact, Japanese Knotweed has been used in traditional herbal medicine in various cultures, particularly in East Asia, for its potential healing properties as the plant contains high levels of resveratrol – which has been linked to cardio-vascular and anti-inflammatory effects. It has also been shown as an effective cure to Lyme’s disease. 

It’s important to note that while Japanese Knotweed shows promise in these areas, scientific research is ongoing, and more studies are needed to fully understand its potential benefits and any potential side effects. Additionally, if considering the use of Japanese Knotweed for medicinal purposes, it’s recommended to consult a healthcare professional or herbalist for guidance, especially if you have any underlying health conditions or are taking other medications. 

Why is Japanese knotweed dangerous? 

In terms of danger, while Japanese Knotweed does not pose a direct threat to humans, it can be highly problematic for buildings. Its astonishing growth rate of up to 10 centimetres a day makes it a formidable force, often targeting weak points in masonry, flood defences, and property foundations. This potential for relentless expansion makes it a significant risk to property owners, potentially leading to extensive structural and financial damage. 

Despite its property-damaging tendencies, Japanese Knotweed is not harmful to humans. In rare cases, some individuals have reported mild skin irritation upon contact, but there is no documented evidence that it was Japanse knotweed that specifically caused the reaction. It is crucial to note that this plant can be mistaken for the more dangerous Giant Hogweed, which could explain the reporting of skin irritation. Therefore, it is essential to correctly identify Japanese knotweed before handling it. 

Worried you may have a case of Japanese knotweed, but unsure? We can help! Simply email us a photo to [email protected] and we will identify it for free!