Pest control

Le Roys Bush is subject to various pests - weeds, animals, pollution and vandalism.

Amongst the pest control projects taking place at present are:

  • The Le Roys Bush weed control framework - managed by the Council Parks Department operated by Te Ngahere Ltd
  • The Little Shoal Bay Wetland weed control programme - managed by Le Roys Bush Committee with funding from the Council and the Birkenhead Trust/Lion Foundation
  • Collaborative projects with land owners neighbouring the Reserve
  • Le Roys Bush Committee working bees
  • The Auckland Council and Le Roys Bush Committee rodent control project coordinated by Te Ngahere Ltd.

Some weed control tips:

All weeds: deal to weed trees like woolly nightshade, privet, acmena, loquat and wattles before they go to seed! If you don't have time to remove them completely, dead head the tree, then come back before the next season and deal to the whole plant.

Woolly Nightshade:  A "controlled" pest plant - a tip from Eco-Science Ltd:

  • Rather than cutting down woolly nightshade, they die better (also make less mess) if you
  • Lightly scrape the bark all around with a paint scraper - about a hand's width from the ground
  • Then apply Vigilant to the wound.
    • Scraping formula is HS = 2D,  or  Height of Scrape = 2 times diameter of tree.


  • Wait till they are about knee high (if you pull them young the root fragments may regrow)
  • Between autumn and spring, while the ground is soft, hold them firmly at the bottom of the stem and pull out roots and all

Acanthus mollis (Bears Breeches):

Mechanical/organic control

Dig out including roots if small enough
Keep stems/roots off ground eg hang in a tree, or may regrow or sprout new roots
Place in sealed black weed bags for 12 months or more to decompose
Deadhead flowers before seeding to avoid seed dispersal

Control methods using herbicide

In reserves, volunteer groups may cut and paint stump with 1-2mm layer picloram gel ensure rim of stump painted (Picloram is commonly sold as "Vigilant")
    Place cut leaves over the top of painted stems to keep rain off.
    Note - don't use picloram near plants you want to keep - the poison travels through the roots to other plants.

People with agrichemical skills may on their own land: Spray with metsulfuron 0.05g per litre, with penetrant 1ml per litre  OR with triclopyr 4ml per litre with penetrant 1ml per litre

Native ground covers:

This note is added to provide some ideas if you want to help prevent weeds growing in your backyard.

Mulch may not look it, but it's the garden's Nivea, a kind of barrier cream to keep in trapped moisture. Pile on composted bark, leaf mould or lawn clippings and it will suppress weeds too.

But this kind of mulch doesn't last forever, says Guy Bowden of Tawapou Coastal Natives. The birds love it, the wind blows it about and "it's not that interesting". So he suggests using native groundcover plants instead.

The key is to match the plant to your local conditions. Guy specialises in plants that thrive by the Northland coast so his range may not suit Southland gardeners. But he reckons coprosmas are the toughest groundcover plants around and says Coprosma repens 'Poor Knights' "can cover a large bank".

A really good cliff plant is Metrosideros perforata, the white climbing rata. For an arid spot on the coast, choose Pimelea prostrata, while Fuchsia procumbens is ideal for very wet places.

"It's the smallest fuchsia in the world and the only one with blue pollen," says Guy. It's also his favourite. "It's a wonderful plant, rather delicate, with lovely fl owers and berries." His tip: feed plants with blood and bone.

Naturally Native's Earth Blanket range is a selection of native groundcovers for most situations. The idea is to mass plant to suppress weeds over a large area. In natural landscapes any bare soil is quickly reclaimed by seedsown or suckering plants, says the nursery's Ruth Russell. "Planting protects earth from being washed away by rain and wind."

Groundcover plants help protect soil, keep roots of taller plants cool and retain moisture in the heat.

Fiona Eadie, author of 100 Best Native Plants for New Zealand Gardens and head gardener at Larnach Castle in Dunedin, loves our native groundcover plants.

"They provide texture within our gardens and berries for the birds, while others fl ower," she says.

"A groundcover is any plant that is low growing (40cm) and that spreads. Itmay have rhizomes, stems that run parallel to the ground and generally under it, like Blechnum penna-marina or Acaena inermis. Or it may simply have a prostrate habit, like Pimelea prostrata, or both like Coprosma acerosa. Herbaceous or woody, it's the form that counts."

Start with Pimelea prostrata, the native daphne, she says "It's available all over New Zealand, and it's very hardy. Its only dislike is wet feet.

"Or prostrate manuka are becoming much more readily available, especially in the North Island. They can be a little taller in their growth habit, but can look totally stunning, often having a cascading habit plus there's a number of different fl ower colours available so you can pick one that suits."

Native picks
Fiona Eadie's top fi ve Kiwi groundcover plants.

• Coprosma neglecta.
It keeps a wonderful tight habit.

• Pimelea prostrata.
Because of the colour of its foliage, this groundcover can be planted with almost anything.

• Acaena microphylla.
This plant has wonderful seedheads that last for ages and don't stick to your socks or sleeves when you are weeding.

• Coprosma brunnea.
It has lovely dark tangly branches, and on the female, blue berries.

• Blechnum penna-marina.
It has the texture of a welldeveloped mat and the new fronds are a lovely pinkybronze colour.

Native Picks - See the numbered image

1. Leptinella 'Platt's Black' has smaller darker leaves than its dioica cousin (number 3).

2. Mazus radicans, the swamp musk. A herb that forms thick patches, it has white flowers. Likes the damp, in sun or shade.

3. Leptinella dioica. For moist shade, it's vigorous and you can walk on it. Green ferny leaves have a touch of bronze.

4. Raoulia hookeri 'Makara'. Compact, it needs good drainage. It grows naturally on shingle so is good for a rockery.

5. Pratia angulata. It quickly covers bare ground and has white flowers over summer, then berries. It prefers a damp spot but copes in most places.

6. Raoulia hookeri 'Makara'.

7. Wahlenbergia gracilis. The native bluebell's a perennial. Plant in sun or semi-shade in well drained soils. Self seeds.

8. Acaena inermis 'Purpurea'. This prickle-free bidibid is best in a sunny moist spot.

9. Isotoma fluviatilis. In damp or dry places, it forms a thick mat which produces heaps of blue star-like flowers in spring and summer.

10. Pimelea prostrata 'Misty Blue'. Landscapers like this one, says Naturally Native's Ruth Russell. It's pretty with blue leaves and white flowers, ideal for dry coastal conditions. It's perfect for covering northfacing banks.

11. Mazus radicans.

12. Pimelea prostrata 'Misty Blue'.

13. Scleranthus biflorus. A riverbank dweller, it likes moisture at its roots so don't water from above. Keep it off soil too or it will go brown and turn up its toes.

14. Isotoma fluviatilis.

15. Acaena inermis 'Purpurea'.

• Plants from the Earth Blanket range by Naturally Native (available at garden centres).