Parrot Feather Milfoil (Myriophyllum aquaticum)

Parrot feather milfoil

Myriophyllum aquaticum


  • Native to South America
  • Aquatic plant with emergent and submerged plant parts
  • Looks like tiny bright green fir trees growing on the water
  • Stiff, feather-like foliage (can extend up to 30 cm above the water’s surface)
  • Leaflets arranged in whorls of 4–6 around the stem
  • Spreads readily through fragmentation of the stems and rhizomes
  • Popular/common aquarium plant

Consequences of invasion

  • Forms dense mats of vegetation that can entirely cover the surface of the water
  • Impedes boating, swimming, and fishing
  • Provides ideal habitat for mosquito larvae
  • Outcompetes native aquatic vegetation
  • Impacts waterways, irrigation ditches, and drainage canals, where it has the potential to inhibit flow and increase maintenance costs
  • Alters water chemistry which can negatively affect juvenile salmon

Status in the CKISS region

Integrated pest management options

  • Never discard aquarium contents into water bodies
  • Purchase alternative, non-invasive aquatic plants for aquariums and aquatic gardens
  • Remove any plant material from boats, anchors, trailers, fishing gear and other equipment before leaving the water body
  • Because this plant spreads readily through fragmentation, mechanical controls such as cutting and harvesting are not recommended

Additional Resources