Popular garden plants are heading for a national ban, regardless of whether the Auckland Regional Council adds them to its controversial hit-list of new pest weeds.

The ARC is the first council in the country to suggest banning the sale, propagation and distribution of the introduced agapanthus, English ivy, Norfolk Island hibiscus, phoenix palm, bangalow palm and Chinese fan palm.

ARC biosecurity manager Jack Craw says the council is looking at adding them to the banned list from next year, because research showed they were invasive and/or poisonous and crowding out native plants.

Palm enthusiasts and nurseries say such action would be heavy-handed and ruin a popular style of subtropical gardening and a booming business.

But Mr Craw said a national ban might take the matter out of ARC hands before it had chance to hear submissions and form a draft strategy.

Agapanthus and English ivy are also top contenders for the revised National Pest Plant Accord, which is backed by the Biosecurity Act and means prosecution for nurserymen who continue to grow and sell them.

Biosecurity New Zealand is taking submissions on the amended accord list until February 10 and says a decision will be made by March.

Mr Craw said any plants rejected for the national accord would still be considered for an Auckland ban.

Landcare Research scientists yesterday supported any ban, calling Auckland "the weediest city in the world", with 220 weeds, and rising.

Botanist Peter Williams said Auckland had more than 10,000 exotic plant species compared with 400 natives. Exotic species were escaping their gardens and seeding in the wild.

Responding to the threat before plants became weeds was crucial for stopping the weed rampage.

He said palms spread slowly - but so did major enemy weeds such as hieracium and old man's beard, which took decades to spread.

The Palm and Cycad Society's 300 members have formed a taskforce to fight any palm ban and are linking with other groups.

Nursery and Garden Industry Association spokesman Bob Wynyard said most of the 51 plants in the suggested ban were neither sold nor propagated and were genuine weeds.

"However, our members are upset about the palms and agapanthus."

Agapanthus were widely used in gardens around the country and brought a lot of life and colour to public places such as motorway berms, where nothing else grew.

"People's rights are being walked over," said Mr Wynyard.

The association had 600 members who wanted a say on any ban that would hurt their businesses.

Titirangi gardener Euan Macduff said garden lovers would be horrified to discover proposals to ban popular plants such as agapanthus, Norfolk Island hibiscus and queen of the night.

"They are pleasant plants. Meanwhile, real weeds like brush wattle and privet continue to thrive in bush reserves, roadsides and public domains."

At Sun Hill Garden World in St Heliers, assistant manager Aaron Dale said any ban would hit one of the nursery's top sellers at $7 to $15 each.

"People like to use [agapanthus] on banks to stop landslides and for filler plants.

"But I can see they are invasive if not controlled."

Local and National Strategies

* The ARC proposes to add 51 exotic plants to a sales ban list, including phoenix, bangalow and Chinese fan palms, and agapanthus, English ivy and Norfolk Island hibiscus.

* Public comment closes on February 28.

* Meanwhile, the National Pest Plant Accord, which bans the sale of particular plants, is being amended by Biosecurity New Zealand.

* This proposes to include the above plants except for the Chinese fan palm

* Public comment closes on February 10.

* Any plants rejected for the national accord will be considered for the ARC ban.

Blacklist Candidates

* Agapanthus praecox (including cultivars and hybrids): Thrives in dry, sunny places and has large blue or white flowers. Seeds dispersed by wind.

* English ivy (Hedera helix): Tough, fast-growing vine that can strangle trees. Used as ground cover in shade.

* Norfolk island hibiscus (Lagunaria patersonii): Pink, mauve flowers, grows to 12m in full sun. Seed pods contain fine, sharp hairs that cause skin to itch.

* Phoenix palm (Phoenix canariensis): Hardy, adaptable and spines can inflict poisonous wounds.

* Bangalow palm (Archontophoenix cunninghamii): Grows to 30m, smooth slender trunk similar to the native nikau palm.

* Chinese fan palm (Trachycarpus fortuneii): Cold-hardy, hairy trunk, seeds readily germinate.