Halt the invasion! All sounds very serious, but the situation is rapidly deteriorating and the more we ignore it the worse it will get.

Non-native invasive weeds (NNIW) should not be under estimated, they are extremely difficult and costly to control and the longer they are ignored the more costly it gets. For example, it has been suggested in the press that the cost of eradicating Japanese Knotweed from a 10 acre area of the 2012 Olympic Park in London could be as much as £70million. Although this may be an overestimation it illustrates the very high cost of control.

Some of these weeds find weak spots and cracks and undermine structures and construction materials such as concrete and tarmac resulting in significant repair costs. There are reports and photos of Japanese Knotweed growing up through the floor in peoples houses.

Non-native invasive weeds have an adverse effect on our local environments and our native species. Problem NNIWs out-compete important native species resulting in their disappearance from some areas and often cause increased erosion of soil. These weeds generally grow and spread very rapidly and can become established in most environments. In many cases human activity is the main mechanism for the spread of such weeds due to the general lack of knowledge about these weeds.

Himalayan Balsam

Japanese Knotweed

Giant Hogweed

NNIWs are now thought to be present in every 10km square in England. There are a number of weeds in the UK that are now classified as invasive, the best known 3 being Japanese Knotweed, Himalayan Balsam and Giant Hogweed. (see photos above). They are quite distinctive when you know what you are looking for (see further information). There are however other lesser known invasive weeds and many more plants that have been identified as potential future invasive weeds, some of which can still be purchased in some garden centres.

The Avon Invasive Weed Forum is an independent group who are aiming to raise the awareness of non-native invasive species in Avon, work out where they are, work with other organisations to attempt to control them, and provide current accurate information to anybody needing to know more about these weeds and their control. For more information about who we are see the Who page.