Weeding out Alien Species
A
new project to tackle invasive non-native plants which threaten important
wildlife rich sites in the county has been launched. The project will focus on
five particularly invasive non-native plant species, namely Japanese Knotweed,
Himalayan Balsam, Giant Hogweed, American Skunk Cabbage and New Zealand
Pygmyweed.
These plants were originally introduced to the UK as ornamental garden plants. Since then, they have jumped the garden fence and have established themselves in the countryside where their vigorous growth can out-compete native vegetation. They can spread rapidly, especially where their seeds are carried along by streams and rivers.
It is vitally important that action is taken to prevent the spread of these aggressive plant species. The project aims to help farmers and landowners who have any of these invasive plants on their land, by giving advice and arranging work to eradicate them or control their growth.
For further information about the project, please contact Catherine Chatters, at the Hampshire and Isle of Wight Wildlife Trust on 02380 424205 or catherinec@hwt.org.uk , or see www.hwt.org.uk
Japanese
Knotweed is native to Japan, Taiwan and Northern China and was introduced to
Europe in the early 19th century. In Britain it first became naturalised in
South Wales, growing on coal tips as early as 1886 and has since become widely
established. It can colonise most habitats such as river banks, woodlands,
grasslands and coastal areas.
Giant
Hogweed is a native of the Caucasus mountains between Russia and Turkey and was
introduced to Britain as an ornamental plant in the late 19th century. It is a
perennial plant which can grow up to 5 metres tall and up to 1 metre across.
Each plant can produce more than 50,000 seeds per year which are dispersed by
wind and water.
Himalayan
Balsam is native to the Western Himalaya and since it was introduced in 1839 it
has spread throughout the British Isles, particularly in recent years. It grows
up to 3 metres high and each plant can produce 800 seeds which are dispersed
explosively from the seed pods.
American
Skunk Cabbage is a native of western North America and was introduced to Britain
in 1901. It has a heavy, musky scent which attracts pollinating insects to its
flowers in the spring. It can grow in many different environments and reproduces
prolifically.
New
Zealand Pygmyweed, native to Australia and New Zealand, was introduced in the
early 20th century as an oxygenating plant for ponds and, since the 1970s, has
spread rapidly. It can colonise many different habitats ranging from damp ground
0.5 metres above water level to depths of 3 metres.