Mistflower

Native to Mexico and Central America, mistflower is a sprawling perennial herb with small white flowers.

Introduced to South East Queensland as an ornamental plant, it quickly invaded disturbed areas. Mistflower can reduce pasture production and also crowd out native vegetation along creeks and in other moist, shaded areas.

Mistflower is not a prohibited or restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Ageratina riparia

Other names

  • Creeping crofton weed, cat's paw, mistweed

Description

  • Sprawling, low-growing perennial herb, 40-60cm tall.
  • Stems have roots at joints that touch ground.
  • Leaves are opposite, generally 7.5cm long and 2.5cm wide, toothed along edges, tapered at each end.
  • Flowers are small, white.
  • Branches end with dense heads.
  • Seeds are black, slender, angular, 2mm long, with fine white hairs at tip.

Habitat

  • Prefers shaded, damp creekbanks, damp hillsides among rocks, and other sheltered, moist places.
  • Has invaded number of steep hillsides and roadsides in wetter plateau areas, with preference for south-facing slopes.

Distribution

  • Found mainly in South East Queensland.
  • Some infestations in north Queensland.

Life cycle

  • Budding occurs around July-August, with full flowering August-October.
  • Seeds germinate in late spring to summer.
  • After flowering, top dies and plant reshoots from base.

Impacts

Environmental

  • Invades bushland and disturbed areas on frost-free slopes.
  • Dominates riverine groundcover habitats.

Economic

  • Invades pasture.

How it is spread

  • Seeds spread by wind and flowing water.

Control

Mechanical control

  • Pull out small plants and ensure proper disposal by burning or putting into plastic bags to rot down.
  • Cultivation, grubbing, hoeing and burning where appropriate, followed by planting of competitive pastures, or replanting with native vegetation, will control mistflower. However, mechanical methods other than hand-pulling may not be feasible on steep, rocky hillsides or over large areas.

Herbicide control

  • Herbicides are effective.

See the mistflower fact sheet (PDF, 770KB) for herbicide control and application rates.

Biological control

  • A white smut fungus Entyloma ageratinae, a proven biological control agent in other countries, is now present in Australia, and is severely damaging mist flower infestations.
  • A stem gall fly, Procecidochares alani, was introduced from Hawaii and released in Queensland in 1987. It has had little impact on mistflower plants.

Legal requirements

  • Mistflower is not a prohibited or restricted invasive plant under the Biosecurity Act 2014. However, by law, everyone has a general biosecurity obligation (GBO) to take reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control.
  • Local governments must have a biosecurity plan that covers invasive plants and animals in their area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.

Further information