NZTA extending campaign to eradicate motorway pest plants


The NZ Transport Agency's Auckland Motorway Alliance (AMA) is stepping up activities to remove unwanted pest plants from the city's motorway network.

The AMA, which maintains the region's motorways and state highways, has spent the past few months removing pest plants from State Highway 1 (SH1) north of the Auckland Harbour Bridge and is now concentrating its eradication programme closer to the central city.

The work is part of five year collaboration with Auckland Council to remove 32 identified pest plant species including privet, woolly nightshade, gorse, moth plant, brush wattle.

"These are plants with little or no value - they self-propagate in the wild and are a risk to drivers and property owners alike," says the AMA's manager of the eradication programme, Rick Gardner.

"They thrive in that fairly inaccessible strip of land along the motorway corridor between the edge of the highway and the NZTA's land boundary."

Starting this Monday, 12 March, the AMA will eradicate pest plants on the Southwestern Motorway (SH20), George Bolt Memorial Drive (SH20A) and Puhinui Road (SH20B) during the next three to four months. Ongoing eradication work, planting and maintenance will also continue for the next four years on SH1 south of the Auckland Harbour Bridge.

The AMA will replace the pests with native trees, bushes and shrubs which have significant life spans and require low maintenance, such as pohutukawa, manuka, akeake, karamu, kowhai, nikau and cabbage tree. Rare plants like kakabeak are also being reintroduced.

As the AMA clears the motorway corridor, Auckland Council will be working with neighbouring residents to remove pest plants from their properties to reduce the risk of re-infestation.

Some areas have a major infestation of pest plants and the work to remove them will have a greater impact on neighbouring communities. These include:

  • SH1 adjacent to Howe Street (northbound between Hopetoun Street and Wellington Street)
  • SH1 Wellesley Street offramp (eastbound)
  • SH1 between Penrose and Mount Wellington (southbound)
  • SH1 between Ellerslie and Panmure (both directions)
  • SH16 Grafton Gully (westbound) to SH1 (southbound)
  • SH16 Newton to St Lukes (both directions)

Mr Gardner says getting rid of the pests is noisy and the AMA has to use chainsaws, chippers and hydraulic excavators.

"For this reason most of the removal work will be done during the day. There will, however, have to be some work at night. We will keep communities informed of our timetable and give as much warning as we can."

Mr Gardner says the eradication programme will also impact on motorway drivers. Traffic management plans will be activated to divert traffic when necessary so workers can remove pest plants safely.

"This job will leave the motorways not only looking nicer, but they'll also be easier and safer places for driving because there will be less need to disrupt traffic for maintenance to get rid of these unwanted pests," Mr Gardner says.