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Bitter weed


Have you seen Bitter weed?

Be on the lookout for Bitter weed and report it to Biosecurity Queensland. Early detection and reporting are the key elements in controlling Bitter weed.

Call us on 13 25 23.

Native to south-eastern USA and Mexico, bitter weed is a compact annual with small yellow flowers.

Bitter weed is poisonous to livestock and competes with pasture and native vegetation. In Queensland, it has been found at only 1 location, near Mount Tarampa in the Lockyer Valley.

Bitter weed is a prohibited invasive plant under the Biosecurity Act 2014.

Scientific name

Helenium amarum


  • Annual herb up to 60cm tall, compact and bushy under favourable conditions.
  • Stems are smooth and branching with numerous leaves.
  • Leaves are smooth, narrow, thread-like, light green to gray-blue.
  • Flowers are yellow, daisy-like, about 2cm in diameter.
  • Unnoticed when competing with other plants, producing a single flower on plants as small as 5cm tall.


  • Prefers open fields, roadsides and disturbed areas in subhumid, warm temperate and subtropical areas where annual rainfall does not exceed 1,000mm.


  • Only known to exist at a single location near Mt Tarampa in Lockyer Valley in South East Queensland.

Life cycle

  • Flowers mostly over spring and summer.
  • Scented flowers are pollinated by insects such as bees and butterflies.
  • Mature seeds are non-dormant and germinate readily in sunlight.

Affected animals

  • sheep
  • horses
  • cattle



  • Competes with native vegetation.


  • Potential weed of pastures.
  • Poisonous to stock, including sheep, horses and cattle.
  • Taints milk of dairy cattle.

How it is spread

  • Seeds in hay, silage and on vehicles.


Physical control

  • Hand-pull, ensuring entire root system is pulled up.

Herbicide control

  • Broad-leaf herbicides such as 2,4-D or Grazon P+D® can be effective.

Biological control

  • No known biological control agents.

Legal requirements

  • Bitter weed is a prohibited invasive plant under the Biosecurity Act 2014.
  • It must not be kept, moved, given away or sold without a permit.
  • The Act requires that all sightings to be reported to Biosecurity Queensland within 24 hours.
  • By law, everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to minimise the risk of bitter weed spreading until they receive advice from an authorised officer.

Further information