New plants suggested for pest control

08 December 2005

Environmentally damaging plants including agapanthus, phoenix palm and English ivy, are being suggested for possible inclusion in the Auckland Regional Council's Regional Pest Management Strategy 2007 - 2012.

The ARC has just released a discussion document describing possible changes to which pest plants it controls and how it controls them. Aucklanders are being asked to provide feedback by 28 February 2006.

The discussion document, Protecting Our Natural Environment, is the starting point of a process to create a Regional Pest Management Strategy for 2007 - 2012. There will be a number of opportunities for the public to offer feedback and submissions on the strategy.

Sandra Coney, Chair of the Parks and Heritage Committee, says the ARC's current pest management strategy has been successful in controlling some pest plants.

"Significant progress has been made controlling old man's beard, African feather grass, green cestrum, cathedral bells and 20 other high-threat species.

"We are looking at adding new plants because scientific research shows they are invasive and/or poisonous. They include agapanthus, English ivy, Norfolk Island hibiscus, phoenix, bangalow and Chinese fan palms."

ARC Biosecurity Manager Jack Craw says the council has been monitoring the detrimental effects of these plant species.

"The ARC is now so concerned that we are proposing that these plants should go into the strategy's Surveillance category, which means their sale, propagation and distribution is banned across the region," he says.

"We are also proposing changes for other plant species in the Total Control and Containment categories.

"We want to hear the regional community's views on our suggestions by 28 February next year."

New measures are also being proposed for dealing with animal pests. This could cover some exotic freshwater fish species, wild sulphur-crested cockatoo and feral cats.

Copies of Protecting Our Natural Environment, which include a questionnaire, are available from www.arc.govt.nz/biosecurity or by calling (09) 366 2000. Feedback on the discussion document closes on 28 February 2006. Workshops will be held for those groups or individuals who need more detailed information. A new draft strategy will be released for public consultation from 30 June to 31 August 2006.

Background information

Agapanthus

A problem all over the Auckland region, agapanthus is highly invasive and can live in a wide range of habitats. It prefers coastal areas and roadsides where its dense clumps block drains, causing localised flooding. Its seed is spread by wind and water and it out competes native plants. Rhizomes are also spread by planting or by dumping. It is a particular problem on the steep coastal cliffs at Piha, Anawhata and Karekare.

English ivy

A rampant, tough, fast-growing vine which strangles its host plant. It can also block spouting, penetrate wooden weatherboards and damage property. Seed spread by birds. Causes allergic reactions in some people. Can completely cover the ground and block out native plants. Ivy strangles native trees and eventually kills them. Also a problem in pine forests.

Phoenix palm

Now naturalising in Duder Regional Park, Waiwera, Wenderholm, Laingholm and on Waiheke and Pakatoa. Seed spread by birds. Mature trees provide copious amounts of seed. Seedlings are shade and salt-tolerant and can even grow in mangrove areas. Very adaptable; it doesn't mind poor soil, is frost-hardy and will grow on pasture. Very difficult to kill. Its spines are harmful to people and animals. Between 1992 and 1997, 21 children were admitted to Starship Hospital with phoenix spine wounds.

Bangalow palm

Fastest growing palm in NZ. A native of Australia, seed spread by birds. It can produce hundreds of seedlings, which suppress other plants. Has invasive properties and out-competes nikau palm.

Chinese fan palm

Also known as windmill palm and Chusan palm, its trunk is usually covered in a loose fibrous mat, which falls off in older palms. Is one of the most cold-hardy palms and tolerates a broad range of soils, is moderately salt and drought tolerant, and readily germinates. Native to temperate and subtropical Asia. In Switzerland it is displacing native species, and reported as weedy in Victoria, Australia. Very long-lived, it forms monocultures (ie pure stands), displacing other plants. It has spread and established mature trees in Auckland, Kawau and Little Barrier Island.

Norfolk Island hibiscus

Norfolk Island hibiscus is just starting to naturalise here and has been found in Shakespear Regional Park, at Muriwai and on Motatapu. It grows rapidly, forms dense stands, sets seed at a young age, tolerates maritime habitats and is a potential threat to coastal vegetation and human health. The fruit contains silicon crystals, which if handled or imbedded into clothes, can cause skin irritation. It's also referred to as the 'itch tree' and 'cow itch tree' and has caused trees to be removed from some areas of Australia.

ENDS

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