Parrot's feather (Myriophyllum aquaticum)

Parrot's feather

Top facts

  • Parrot’s feather is named for the feather-like appearance of its leaves.
  • An aquatic plant, parrot’s feather grows both above and below the water, producing submerged as well as emergent leaves.
  • Although native to South America, parrot’s feather has been introduced to many other parts of the world, where it is considered to be invasive.
  • Only female plants occur outside of the native range of parrot’s feather, meaning that seeds are not produced and all reproduction is vegetative.
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Parrot's feather fact file

Parrot's feather description

GenusMyriophyllum (1)

Parrot’s feather (Myriophyllum aquaticum) is a perennial aquatic plant which is named for the distinctive, feather-like appearance of its leaves (3) (4) (5) (6) (7). Pale blue-green in colour and finely divided into thread-like segments, the leaves grow in whorls of four to six around the stem (2) (3) (4) (5) (6) (8) and give the overall appearance of a miniature fir tree (4) (7) or bottlebrush (8). The genus name of parrot’s feather, Myriophyllum, comes from the Greek for ‘innumerable’ and ‘leaf’, referring to the leaves’ numerous feathery segments (5).

Parrot’s feather grows both above and below the water, producing submerged as well as emergent leaves. The emergent leaves tend to be slightly larger and stiffer, while the submerged leaves are more fragile and decompose quickly (3) (4) (7) (8). The emergent stems of parrot’s feather can extend up to 30 centimetres or more above the water’s surface (4) (8). Underwater, parrot’s feather forms a dense mat of long, brown, intertwined stems, with roots at intervals along their lengths (3) (4) (5) (6) (8).

The flowers of parrot’s feather are tiny and inconspicuous, and grow at the bases of the emergent leaves. Each flower is white and is around 1.5 to 2 millimetres in length (3) (4) (5) (6).

Also known as
Brazilian water milfoil, Brazilian watermilfoil, parrot feather, parrot feather watermilfoil, parrotfeather, parrot's-feather, thread-of-life.
Enydria aquatica, Myriophyllum brasiliense, Myriophyllum proserpinacoides.
Stem length: up to 2 m (2) (3)

Parrot's feather biology

Parrot’s feather is reported to flower in the spring (3) (4) (6), producing male and female flowers on separate plants (5). However, only female plants occur in this species’ introduced range (4) (5) (6) (8), and even in its native South America male plants are rare (4).

As no male flowers occur outside of South America, parrot’s feather does not produce seeds in its introduced range. However, this plant can spread rapidly by vegetative reproduction, producing new plants from fragments of stem (4) (5) (6) (8).

Parrot’s feather dies back in winter, but as temperatures increase in spring new shoots quickly appear from overwintering rhizomes (3) (4) (5) (6) (8).


Parrot's feather range

Parrot’s feather is native to South America, but has been introduced to many other areas around the world, including North America, South Africa, Japan, Australia, New Zealand, the United Kingdom, France, and parts of Africa and Southeast Asia (4) (5) (8) (9).


Parrot's feather habitat

An inhabitant of still or slow-flowing freshwater, parrot’s feather grows in a range of aquatic habitats, including lakes, ponds, streams, canals, ditches and reservoirs (2) (4) (5) (6) (8) (9). This species is usually found in nutrient-rich waters (3) (4) (6) (9). Although it grows best in shallow water, it can sometimes grow as a floating plant in deeper water and can also extend onto mud and gravel along the shore (4) (5) (8). Parrot’s feather often forms dense mats which entirely cover the water’s surface (4).

Although it grows fastest in tropical regions, parrot’s feather can also survive in cooler areas, with the plants lying dormant when the water surface freezes over (5).


Parrot's feather status

Parrot’s feather has yet to be classified by the IUCN.


Parrot's feather threats

There are not known to be any major threats to parrot’s feather in its native range. Where it has been introduced, mainly as a result of escapes from aquariums and garden ponds, this species is considered to be invasive, quickly taking over pond and lake habitats. Parrot’s feather can easily be spread by fragments of stem moved around on machinery, boats, or even on clothing or on animals (4) (6) (8) (9).

This invasive aquatic plant may potentially cause a number of problems in its non-native range. For example, it may out-compete native plants, reduce the amount of sunlight entering the water, deplete oxygen levels, and create ideal breeding habitat for mosquitoes. Dense mats of parrot’s feather can also cause flooding by blocking water courses and drainage channels, and may restrict recreational activities and interfere with fisheries (3) (4) (6) (7) (8) (9).

If male plants were introduced into the non-native range of parrot’s feather, it could lead to seed production and even more rapid spread of this species (5).


Parrot's feather conservation

No specific conservation measures are currently known to be in place for this species in its native South American range. In the United Kingdom, parrot’s feather is listed under Schedule 9 of the Wildlife and Countryside Act with respect to England, Wales and Scotland, making it an offence to plant or otherwise allow this species to grow in the wild (3) (6). In Washington, U.S., it is illegal to purchase, trade or sell parrot’s feather (4). An invasive species action plan in place for this plant in Ireland aims to prevent its further spread and sets out actions required to control it (7).

Once established in an area, parrot’s feather can be difficult to eliminate completely (4) (6). A thick, waxy layer on its stems and leaves makes it difficult for herbicides to enter the plant, and mechanical cutting can create stem fragments which may regenerate (4) (7) (8). A combination of more than one control method is usually needed over several years (6).

Parrot’s feather contains high levels of bitter tannins, meaning that most animals find it unpalatable and do not graze on it (4) (6) (8). However, biological control of this species may be possible using certain insects from its native range (4) (5) (8) (10). Covering up patches of parrot’s feather to shade it for several weeks may also be one way of restricting its growth (5) (7).

Recommended measures to prevent the further spread of parrot’s feather include locating all existing introduced populations, identifying and monitoring areas most vulnerable to new invasions, restricting sale of this species, and raising public awareness of the problems it can cause (6) (7).


Find out more

Find out more about parrot’s feather:



This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:



Aquatic plants whose stems and leaves extend beyond the water’s surface.
A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
A plant that normally lives for more than two seasons. After an initial period, the plant produces flowers once a year.
An underground, horizontal plant stem that produces roots and shoots.
Vegetative reproduction
Type of asexual reproduction (reproduction that does not involve the formation of sex cells) in which a new plant grows from part of another plant, rather than from seeds or spores. The resulting individual is genetically identical to the original plant.
In plants, a set of leaves, flowers, or branches that spring from a stem at the same point and encircle it.


  1. Integrated Taxonomic Information System (ITIS) (September, 2013)
  2. Streeter, D., Hart-Davies, C., Hardcastle, A., Cole, F. and Harper, L. (2009) Collins Flower Guide. HarperCollins Publishers, London.
  3. GB Non-native Species Secretariat (NNSS): Identification Sheet - Parrot’s feather (September, 2013)
  4. Washington State Department of Ecology: Non-native Invasive Freshwater Plants - Parrotfeather (September, 2013)
  5. Parsons, W.T. and Cuthbertson, E.G. (2001) Noxious Weeds of Australia. Second Edition. CSIRO Publishing, Collingwood, Australia.
  6. Sussex Wildlife Trust - Parrot’s feather fact sheet (September, 2013)
  7. Kelly, J. and Maguire, C.M. (2009) Parrot’s Feather (Myriophyllum aquaticum) Invasive Species Action Plan. Prepared for NIEA and NPWS as part of Invasive Species Ireland, Ireland. Available at:
  8. Bossard, C.C., Randall, J.M. and Hoshovsky, M.C. (2000) Invasive Plants of California’s Wildlands. University of California Press, Berkeley and Los Angeles.
  9. GB Non-native Species Secretariat (NNSS): Factsheet - Parrot’s feather (September, 2013)
  10. Cilliers, C.J. (1999) Biological control of parrot’s feather, Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae), in South Africa. African Entomology Memoir, 1: 113-118.

Image credit

Parrot's feather  
Parrot's feather

© Erwan Balança / Biosphoto

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