Japanese Knotweed

Absolute tree care fully qualified and licensed to treat Japanese Knotweed and Giant hogweed with knapsack spay and stem injection.

Japanese knotweed (Fallopia japonica var japonica) is a non-native invasive species of plant. Since it was introduced into the UK as an ornamental garden plant in the mid-nineteenth century it has spread across the UK, particularly along watercourses, transport routes and infested waste areas.

What Japanese Knotweed looks like.


Giant hogweed (Heracleum mantegazzianum}, is a native of the Caucasus mountains and was introduced to Britain in 1893 as an ornamental plant. It escaped from gardens and now colonises many areas of wasteland and riverbanks. Each flower head produces several thousand seeds that are easily dispersed by water, so the plant spreads rapidly along watercourses.

It is a perennial plant, taking up to four years to mature and flower, after which it dies. It forms dense colonies that suppress the growth of native plants and grasses, leaving the banks bare of vegetation in winter and increasing the risk of erosion and recolonisation from seeds washed downstream.

Growth starts in March and the plants reach Sm in height. The leaves are dark green, and form a rosette. The lobes are deeply cut and spiked at the ends. The stems are green with dark red or purple spots or blotches. Stems are ribbed, with sparse spiky hairs on the ridges. The stems are hollow and up to 100mm across.

The flowers are white, forming a large umbel. Each plant produces up to 50,000 seeds, approximately 10mm long by 7mm wide. Seeds may remain viable for up to 15 years.

What Giant Hogweed looks like.



It is an offence to plant or cause Japanese knotweed to spread in the wild under the Wildlife and Countryside Act 1981 and all waste containing Japanese knotweed comes under the control of Part II of the Environmental Protection Act 1990.

The Law of Nuisance   

Common law recognises the civil wrongs of nuisance, both private and public. A private nuisance is defined as an “unlawful interference with a person’s enjoyment of land, or some right over, or in connection with it” (Read v Lyons & Co Ltd 1945) and only a person with a legal right to exclusive possession may sue. A public nuisance occurs where a large section of the public is affected. If there were a case of public nuisance, it is important for you to establish if the accused person could have ‘foreseen’ this. So, having evidence that you had let the owner of the neighbouring property know about the Japanese knotweed would be important.