Parrotfeather

Parrotfeather

Myriophyllum aquaticum
Parrotfeather-_G-Lovell_Bugwood

Status in Squamish:

PREVENTION-WATCHLIST

Status in Whistler:

PREVENTION-WATCHLIST

Status in Pemberton:

PREVENTION-WATCHLIST
Vectors of Spread:
Synonyms
  • Parrotweed
  • Water feather
  • Parrot’s feather
  • Brazilian watermilfoil
ID Characteristics

General: Parrotfeather is an aquatic plant in the Watermilfoil family (Haloragaceae).

Flowers: Inconspicuous (1.6 mm) white flowers that emerge from the axils of shoots.

Stems: Reddish submersed stems creep along the water surface, while green emergent stems grow vertically up to 30 cm above the water. Stems can grow 2 – 5 m long, with extensive branching throughout.

Leaves: Feather-like leaves are heterophyllous, meaning they exist both above and below water. Emergent leaves have whorls of 4 – 6 leaves per node and appear bright green, waxy and stiff. Submerged leaves have whorls of 3 – 6 leaves per node and are tinged red.

Roots: Parrotfeather has thin, hair-like roots that arise from the nodes of stems.

Fruits: Parrotfeather does not produce seed outside its native range.

Similar Species
Exotic:
  • Cutleaf Watermilfoil (Myriophyllum pinnatum) has darker stems and foliage than Parrotfeather. It is native to Eastern North America. (We were unable to source an image for this species.)
Invasive:

Eurasian Watermilfoil (Photo credit: Alison Fox, University of Florida, Bugwood.org)

  • Eurasian Watermilfoil (Myriophyllum spicatum) also resembles Parrotfeather, but it is reddish-brown and has more pairs of leaflets per leaf (14 – 21).
Report

Please report any sighting of Parrotfeather by clicking here.

Habitat and Origin

Parrotfeather is native to South America and arrived in Canada as an ornamental pond plant.

Parrotfeather’s habitat is limited to non-tidal, freshwater, slow-moving water bodies including tributaries, ponds, lakes and canals. This plant thrives in ample light, alkaline and high-nutrient environments.

While Parrotfeather can withstand mild winters, temperatures in the Sea to Sky Corridor typically reach below tolerable conditions for it to persist year-round, though it’s likely that climate change will be broadening its range.

Current Distribution

Propagation & Vectors of Spread

In BC, Parrotfeather reproduces vegetatively through plant fragments. As male plants are not present outside their native range, female plants cannot produce seeds.

While Parrotfeather does spread vegetatively, humans are a primary means of dispersal. Parrotfeather is commonly purchased for aquaria and aquatic gardens, and can travel long distances by hitching a ride on boats, trailers, and other gear.

Ecological, Economic, & Health Impacts

Ecological: 

  • Can form dense mats that outcompete native aquatic plants, especially in shallow ponds.
  • Impedes water flow and traps sediment.
  • Creates suitable habitat for mosquito larvae.

Economic:

  • Dense infestations can impede the movement of boats, damage equipment, and clog drainage ditches.
What Can I Do?

Parrotweed is not yet found in the Sea to Sky region, but is found in neighbouring areas and may arrive here soon. The goal is to prevent Parrotweed’s introduction by focusing on education and awareness. If prevention fails, the goal will become immediate eradication following the proposed SSISC EDRR protocol.

Learn to identify Parrotweed: use the images presented in this profile page to learn how to identify Parrotweed.

What to do if you spot it: You can report any Parrotweed sighting by clicking here.

DO:

  • Clean, Drain, and Dry all watercraft. Rinse all mud, debris, and plant fragments from all equipment, wading gear, and boats.
  • Ensure all plant parts are bagged and covered during transport to a designated disposal site.

DO NOT:

  • Plant Parrotfeather in an aquarium or a water garden, no matter how well-contained its enclosure may seem.
  • Dispose of aquarium plants into water bodies.
  • DO NOT compost!

Control

Mechanical 

  • Attempting to control Parrofeather by mechanical means tends to spread the plants and should only be conducted with extreme caution, ideally in small, contained water bodies.
  • For larger water bodies, we advise the use of a cloth screen or floating net to contain the treatment area.
  • Raking or hand-pulling may offer temporary control; however, this approach is very labour intensive, as dense mats are heavy and can damage equipment.
  • The benthic barrier method can effectively smother plants: by using an opaque mat, one can block the sunlight and oxygen that are necessary for the plant to survive. However, note that this treatment may impact other species as well.
  • Alternatively, re-planting riparian areas with non-invasive species can create shade and reduce Parrotfeather’s growth.
  • For best results, combine several mechanical control methods and monitor treated sites often.

Chemical

Chemical control is impossible due to the aquatic nature of this plant.

Biological

There is no biocontrol available for this plant.

References

BioNET-EAFRINET, Myriophyllum aquaticum (Parrot’s feather) Factsheet, https://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/weeds/Media/Html/Myriophyllum_aquaticum_(Parrots_Feather).htm

California Invasive Plant Council, Myriophyllum aquaticum, https://www.cal-ipc.org/plants/profile/myriophyllum-aquaticum-profile/

Centre for Invasive Species and Ecsystem Health, Parrot-Feather, https://www.invasive.org/alien/pubs/midatlantic/myaq.htm

Electronic Atlas of the Flora of BC, Myriophyllum aquaticum, https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Myriophyllum+aquaticum

Electronic Atlas of the Flora of BC, Myriophyllum pinnatum, https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Myriophyllum+pinnatum

Electronic Atlas of the Flora of BC, Myriphyllum spicatum, https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Myriophyllum+spicatum

Great Lakes Aquatic Nonindigenous Species Information System, Myriophyllum aquaticum (Vell.) Verdc., https://nas.er.usgs.gov/queries/GreatLakes/FactSheet.aspx?Species_ID=235

Invasive Plant Atlas of the United States, Parrotfeather, https://www.invasiveplantatlas.org/subject.html?sub=3054

United States Geological Survey, Myriophyllum aquaticum (Vell.) Verdc., https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=235