Photo guide to weeds

Siratro (Macroptilium atropurpureum)

  • Siratro flower
    Siratro flower
  • Siratro plant
    Siratro infestation

General information

Native to tropical America, siratro is a creeping or climbing legume that is used as a pasture plant. Siratro has become a problem where there has been a change of land use and cattle are no longer grazed so that the fast growing vine has escaped into roadsides and bushland margins to smother and choke out desirable species.

Siratro is not a declared pest plant under Queensland legislation.


Scientific name Macroptilium atropurpureum
  • Vine with thin stems up to 2m long
  • Leaves are bright-green, 2-7cm long, silky hairs on the underside, with three broad leaflets.
  • Flowers are dark red-purple, pea-shaped, borne on long spikes, 1.5-2.6cm long.
  • Fruit is bean like pods that are narrow, 5-10cm long.
  • Seeds are light brown and black, 4mm long, 2mm wide.
  • Found near roadsides, disturbed sites and areas not grazed by livestock.
  • Native to tropical America.
  • Occurs in coastal eastern Queensland and coastal New South Wales.
Life cycle
  • Flowers throughout the year.
  • Spread by seed and vegetatively.
  • Can also spread by water and livestock.


  • Smothers native shrubs, grasses or young trees.
  • Forms dense infestations along forest edges.
  • Common in vegetation around waterways and in coastal sand dune vegetation.

The best form of weed control is prevention. Treat weed infestations when they are small - do not allow weeds to establish.
Ways to prevent weed spread 


Physical control

  • Can be hand-pulled, chipped or mowed.
  • Use a brush-cutter to clear tangled growth.

Herbicide control

  • Herbicides are effective.

See the siratro fact sheet (PDF, 185KB) for herbicide control and application rates.

Biological control

  • There is no biological control agent available for this plant.
Declaration details
  • not a declared species under Queensland legislation but may be declared under local government law

Last updated 26 February 2014