Parrots Feather (Myriophyllum aquaticum)

Photo: (c) Forest and Kim Starr

Family: Haloragaceae

Growth Habit: A feathery aquatic plant with yellow-green stems that can grow up to 5 m in length. The tips of the stems frequently protrude from the water up to 30 cm. The short leaves grow in tight whorls and are shades of bright yellow and green and feathery in appearance.

Type of Plant: Parrots Feather is a perennial freshwater herb.

Flowers: Flowering rarely occurs in Tasmania due to cooler water temperatures.

Fruit/Seed: Seeds are infertile in Australia due to only female plants being recorded here.

Dispersal: Parrots Feather reproduces by fragments breaking from the parent plant and being moved by water currents. They may grow free-floating for a period before rooting in sediment.

Distribution: Found in shallow water bodies, pools and creeks. Also commonly found in home aquaria as the plant was once sold as an attractive fish tank plant. Like many aquatic weeds, Parrots Feather grows especially well in water with high nutrient levels.

Status: Parrot’s feather is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of parrot’s feather are prohibited in Tasmania.

Weed Impact:

  • Parrots Feather is capable of totally choking water ways, excluding all other flora and fauna.

For further information contact the Department of Primary Industry, Parks, Water and Environment, Tasmania.

Control Methods:

  • Do not dump any aquarium water into waterways.
  • Manual (spring, summer and autumn). Remove all stems and roots.
  • When removing the weed, it is important to minimise the movement of stem fragments downstream to reduce the chance of spread.
  • Disposal (all year). Dry out all material on the ground in the sun. Never dispose of any Parrot’s Feather in ditches, creeks etc.
  • If infestations in small ponds/dams that can be safely drained Parrot’s Feather can be eradicated by allowing to dry out.
  • Infestations in small dams can be effectively controlled by covering the dam with black plastic sheeting for several weeks to ‘cook’ the parrot’s feather.
  • Herbicide (summer). As this plant is located in waterways, herbicidal treatment needs care. Check DPIPWE’s Herbicide for Aquatic Weed Control for further information.

N.B. Always check the herbicide label before use.