” Invasive plant species are now one of the biggest threats to habitats and biodiversity across the world”. (DEFRA)
An invasive non-native species is any non-native animal or plant that has the ability to spread causing damage to the environment, the economy, our health and the way we live.
They damage our environment, the economy, our health and the way we live.
- They threaten our native plants, animals and habitats.
- They cost the British economy over £2 billion each year.
- They can threaten our health.
The total annual cost of invasive non-native species to the British economy is estimated at approximately £1.7 billion. This is said to be a conservative figure and does not include indirect costs which could be substantially higher.
Almost two thirds of our non-native plant species in England are of European origin. After that it’s North America. Non-native freshwater fish species in GB originate mainly from North America and European/Asian continent equally. Australasia is the origin of 38 animals 9 plants that have become established in GB.
Plantlife have a ‘Dirty dozen’ invasive non-native species list of plants that threaten the UK’s flora. These are:
American skunk cabbage (Lysichiton americanus)
Broad-leaved bamboo (Sasa palmata)
Giant rhubarb (Gunnera tinctoria)
Cotoneasters (Cotoneaster spp)
Himalayan Balsam (Impatiens glandulifera)
Hottentot fig (Carpobrotus edulis)
Japanese Knotweed (Fallopia japonica)
Pirri-pirri bur (Acaena novae-zelandiae)
Rhododendron (Rhododendron x superponticum)
Spanish bluebell and hybrid (Hyacinthoides hispanica and H. hispanica x H. non-scripta)
Variegated yellow archangel (Lamiastrum galeobdolon subsp. argentatum)
So what about the Isle of Wight?
Plant Positive is a partnership of organisations that was created to target species such as Japanese knotweed, Himalayan balsam and creeping water primrose that are spreading along the Island’s watercourses. These displace a more natural flora leaving behind habitats and wildlife that are significantly poorer as a result.
Control is focussed on two main river catchments, the Medina and the Eastern Yar where Himalayan balsam, Japanese Knotweed, Creeping Water Primrose and Parrots Feather will be the targets for control. A watching brief will be kept on New Zealand Pigmyweed and Giant Hogweed.
Himalayan balsam has infested the banks of the Eastern Yar, Wroxall Stream and Scotchells Brook. There is also small patches on the Medina River and Merstone Stream at Blackwater. Volunteers participate in an annual campaign to hand pull the plant from these areas.
Japanese Knotweed is rampant across the Isle of Wight, and from a water-course perspective causes us concerns on Wroxall Stream, Lukely Brook and the Medina River. (See below also).
Creeping Water Primrose is a problem in some West Wight ponds where we have been treating it. Its nearly gone!
Parrot’s Feather is prevalent in many ponds and also water courses on the Sandown Levels.
New Zealand Pigmyweed (also known as Australian Swamp-stonecrop) is an issue on the Sandown Levels.
Giant Hogweed is rarely found on the Isle of Wight. It’s highly toxic and contact with any part of the plant can cause serious and recurring blistering of the skin. Do not touch the plant.
Of course, invasive non-natives are not just plants, and although rivers are perfect vectors to enable their spreading, wetlands are not the only habitat where they occur. We have therefore been working together to develop a more holistic plan for the Island. This includes sections on education, pathway prevention, species we want to keep out, or to control, and details who is doing what on the Island. You can read it here.
A full list of non-native invasive plants in the UK can be found online at the Non-Native Species website.
Japanese Knotweed
We get lots of calls about Japanese Knotweed. Whilst our focus is on Island Watercourses, we are happy to chat about it over the phone, and give advice where we can. We have even issued a factsheet which is pertinent to the Island. If you discover Japanese Knotweed, don’t panic, but do get advice from professionals on its removal. If treated early it should be easy to eradicate, and not too expensive. But do shop around as we find there are considerable differences between various Island contractors.
What can you do to help?
You can Be Plant Wise and you can become a volunteer for our Himalayan Balsam control campaign.
Be very careful not to spread these plants. Practice good bio-security. There is lots of useful information accessible from here.
This project is co-ordinated by Natural Enterprise. For more details please call 01983 296244 or email carol.flux@naturalenterprise.co.uk
Our Plant Positive Project is supported by 
