Palm trees popular in landscaping projects will be banned in Auckland under new regional laws.
Enthusiasts for exotic subtropical plants are ready to fight an Auckland Regional Council proposal to ban three palm tree species as pest plants.
The council says that adding phoenix, bangalow and chinese fan palms to a list of plants banned from sale, propagation and distribution will improve pest weed management.
These palms are kingpins in the booming subtropical style of gardening and feature in parks and expensive housing developments.
Introduced to Auckland a century ago, their recent surge in popularity for landscaping projects is alarming native tree advocates.
ARC biosecurity manager Jack Craw said the council was looking at adding the palms to the banned list because scientific research showed they were invasive and/or poisonous.
Public views on banning them were welcomed.
He said research commissioned in 2004 showed self-sown phoenix palms growing in coastal areas and islands, and people wounded by their spines have needed hospital treatment.
"We found half-grown palms that had self-sown into mangrove wetlands, young plants growing in thick kikuyu on the edges of farm paddocks, even seedlings growing alongside native nikau palm in dense bush.
"These plants are being spread into some of our most remote and vulnerable habitats by birds and water. All three species are becoming significant weeds in natural areas."
Bangalow palm, a native of the Australian rainforest, was self-seeding and growing readily in shady bush.
It was aggressively competing in the wild with New Zealand's only native palm, the nikau.
The research report said the hardy chinese fan palm had spread unassisted and mature trees were found in Auckland and Kawau Island.
But the NZ Palm and Cycad Society says the ARC evidence is flimsy.
"It's crazy to say the palms are going to take over the native bush when they've been in New Zealand for a hundred years and they don't act like weeds," said society president Jon Lok. "It should be up to the individual property-owner what is planted - not the ARC."
Mr Lok said the society's 300 members were taking the ban threats seriously and had formed a taskforce to fight it.
Taskforce member John Prince said "tens of thousands" of the palms were planted round Auckland, Mt Maunganui and Whangarei and any self-seeded trees could be easily removed.
Nurserymen said they doubted whether bangalow and chinese fan palms would grow in the wild without help, because they needed 12 to 15 years to become established.
Those who grow, sell and carry the palms would face a big income loss. A 2m-high bangalow sells at an Auckland nursery for $265, a 1.5m phoenix for $150 and a 2m chinese fan, $170.
Demand for the phoenix was already dropping as a result of publicity about poisonous spikes, said Colin Verlaan, whose New Zealand Palm Co propagates most palms planted in the country. Demand for the company's bangalow palms was buoyant at up to 300,000 a year and the chinese fan at 100,000, he said.
Landscape architect Richard Mann said phoenix palms had "lost their gloss" and he preferred the kentia palm as an alternative, because it matched the nikau for beauty.
Forest and Bird northern conservation officer David Pattemore said he supported a strong stance by the ARC to protect vulnerable native species from new plants. He had found self-sown phoenix palms growing in native bush and believed they were a significant threat to nikau seedlings as they took over.
The discussion document Protecting our Natural Environment and a questionnaire are available from the ARC for comment by February 28.
ARC pest palm hit-list
* Phoenix palm (Phoenix canariensis), hardy, adaptable and spines can inflict poisonous wounds.
* Bangalow palm (Archontophoenix cunninghamii) grows up to 30m, has a smooth, slender trunk similar to the native nikau palm but grows faster.
* Chinese fan palm (Trachycarpus fortuneii), cold-hardy, hairy trunk, seeds readily germinate.