Parrot's Feather

(Myriophyllum aquaticum)
Regional Surveillance Pest

(Myriophyllum aquaticum)

Regional Surveillance Pest

Parrot’s Feather is a stout, smooth, freshwater perennial that grows to 2 metres long. Stems either form a floating mat spreading across the water’s surface from marginal areas, or submerged. Emergent leaves are pale bluish-green, featherlike and finely divided. The submerged leaves are often reddish. Parrot’s Feather only spreads vegetatively in New Zealand.

Reasons for the Strategy

A fernlike and feathery stalk laying in a pool of water.

Parrot’s Feather forms dense mats that impede water movement and increase the chances of flooding and siltation. Stems can break off easily and can block irrigation pumps. The control of Parrot’s Feather is very difficult.

Parrot’s Feather is assessed at “3” on the infestation curve. Given how difficult it is to control Parrot’s Feather, the best option is to provide advice and education to stop the spread of Parrot’s Feather, and to monitor and control the existing infestations where possible.


To gather information on the distribution of Parrot’s Feather in the Tasman-Nelson region and prevent the human spread of this pest in the region during the term of the Strategy.

Alternative Measures

The inclusion of Parrot’s Feather in the Strategy, with a focus on advice and education, and surveillance and control by the Management Agency, is appropriate to stop the spread of this plant. The principal alternative measure is to adopt a greater level of regional intervention, such as requiring all occupiers to control infestations of the plant. However, this option is considered inappropriate, given the difficulty of controlling Parrot’s Feather.

Biosecurity Act Requirement

No person shall knowingly sell, propagate, breed, release, or commercially display Parrot’s Feather, under Sections 52 and 53 of the Act.