• Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Prostrate, perennial herb with slender, woody stems
  • Leaves composed of 9-15 pairs of leaflets (pinnate leaves)
  • Leaflets oblong and deeply toothed
  • Flower heads spherical and comprising many segments, each with a long, hooked spike when fruiting

Diagnostic differences

  • A. novae-zelandiae leaves are bright and shiny with pale-green undersides
  • A. anserinifolia leaves are dull brownish-green with silvery, hairy undersides
  • A. anserinifolia also has smaller flower heads.

Origin

  • Both species are native to New Zealand
  • A. novae-zelandiae is also found in Australia and Papua New Guinea
  • It has become a weed in California, Great Britain and Ireland.

Occurrence

  • Common in unimproved pastures, especially in broken hill country, and in waste places
  • Found throughout New Zealand, although is less common on the West Coast of the South Island.

Life cycle

  • Perennial herbs with a stoloniferous growth habit
  • New plants grow from seed
  • Seed dispersal is aided by the hooked spikes, which latch on to and are spread by animals.

Benefits

  • A. novae-zelandiae has been used for ground cover in gardens or as a lawn substitute but more commonly a related species A. inermis purpurea is now used in this role
  • It has been suggested that dried tips of young leaves of A. anserinifolia may be brewed as tea.

Impacts on pasture

  • Invasive in poor or broken pastures, limiting grass growth and pasture utilisation.

Impacts on forage crops

  • Unlikely to invade cultivated or cropped land.

Impacts on stock

  • The hooked seeds latch onto sheep’s wool, interfering with shearing and down grading the value of the fleece
  • Likely to have a similar impact on other fleece bearing animals such as alpaca.

Grazing and cultural management

  • Unaffected by lax grazing or set stocking
  • Mob stocking (heavy on-and-off grazing) may reduce flowering and seed set
  • Improved pastures may reduce the incidence of this weed.

Chemical control

  • The phenoxy herbicide 2,4-D has a label claim to control or severely suppress this weed, however, farmers in some regions say it has little impact
  • Picloram based herbicides may offer greater suppression but will also severely damage clovers
  • Anecdotal reports indicate glyphosate has little impact
  • Effect of metsulfuron unknown.