Weed information |
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Weedy facts | Weeds & people | Weeds are bad | Weed spread | Why do weeds grow better? | Future weeds |
Weedy Facts
The rest of the 40 000 plants are planted in gardens and parks around New Zealand or are being used in agriculture, horticulture or forestry. More than 70% of NZ's environmental weeds were plants that escaped from gardens (they began reproducing by themselves and spread usually by seeds or by people dumping garden rubbish)! Each year, another 12 species of these introduced plants escape and naturalise (go wild) and some of these will become weeds. In New Zealand there are 500 plant species that are weeds - they are controlled by farmers, forestry, regional councils or the Department of Conservation. We have more than 276 environmental weeds, these are the weeds that invade native vegetation and harm our unique biodiversity. The list of weeds is growing and weeds are still spreading around New Zealand! Since European settlers came, 144 new plant species have been arriving each year (on average). That is the same as one new plant species every 2-3 days!! $40 million is spent each year in New Zealand monitoring ports and airports for new plant arrivals and preventing weed introduction and spread. $60 million is lost in production to New Zealand agricultural industries. An estimated $350 million is spent on controlling weeds in New Zealand! |
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Some New Zealand native species have become major weeds in other countries:
- harakeke (flax - Phormium tenax) is a weed on the remote island of St Helena
- pohutakawa (Metrosideros excelsa) is a big problem in South Africa
- karaka (Cornyocarpus laevigatus) is a menace in Hawaii
- pigmyweed (Crassula helmsii) costs Britain $3 million each year to control
Where do New Zealand's environmental weeds come from?
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Weedy facts | Weeds & people | Weeds are bad | Weed spread | Why do weeds grow better? | Future weeds