Native plants outnumbered

Cook's scurvy grass has medicinal value. Picture / John Smith-Dodsworth

New Zealand's native plants are officially in a minority for the first time, out-numbered by wild exotic species.

New Zealand has about 2350 native plant species but exotic plants that have naturalised in the wild now number 2400, according to records from the country's herbariums, or plant collections.

New plants are added to the collections by botanists, regional councils, Biosecurity New Zealand and the Department of Conservation and it is the first time exotics have outnumbered natives.

"It's just appalling really," said New Zealand Plant Conservation Network spokesman John Sawyer.

"This is a major milestone for the country but it's a step backwards.

"We've got major problems in the future if we want to keep native plants thriving."

Auckland Museum botany curator Ewen Cameron said of about 25,000 exotic species cultivated in New Zealand gardens, around 10 per cent now grew in the wild.

It was estimated about 15 new exotic species naturalised in New Zealand each year.

"It's a very big concern that the number is increasing at such a rate," he said.

"Even if we allowed no new plants, the ones already in people's gardens will jump the fence for decades or centuries to come."

Plants such as privet, climbing asparagus, old man's beard and ginger were out of control and the only hope to limit their spread was bio-control. The recent introduction of the tiny gall fly to help control the invasive mist flower weed offered some hope for the future, he said.

Mr Cameron said Cook's scurvy grass, voted New Zealand's favourite plant in the network's website poll, was listed as threatened and was an example of a native plant under threat from foreign species.

The grass was once common.

"You would struggle to find it anywhere in the North Island now," he said.

 
* * *

The silver fern might be New Zealand's sporting symbol but Captain Cook's scurvy grass has been voted the country's favourite plant in an online poll.

Lepidium oleraceum, fed to Cook's crewmen to fight the disease scurvy caused by a lack of vitamins including vitamin C, is New Zealand's number one plant, according to the New Zealand Plant Conservation Network's poll.

Second on the list was coastal kowhai (one of eight species of kowhai) and third was the Poor Knights lily, voted number one by Aucklanders.

Mr Sawyer said more than a 1000 people had cast a vote but the eventual winner was a surprise.

"Should the All Blacks lose the silver fern from their rugby jerseys or should our netball team become the Golden Kowhai?" he said.

Pohutukawa had won the vote for the past two years but didn't make the top 10 this year.

Regional results included the cabbage tree, voted top plant by Wellingtonians, and Taranaki voters favouring the nikau palm.