Parrot Feather (Myriophyllum aquaticum)

Family: Watermilfoil family (Halogaraceae)

Description

Parrot feather is an herbaceous aquatic plant native to the Amazon region that inhabits lakes, ponds, and quiet streams. Its underwater stems reach 15-20 feet in length. One of the most distinctive features of the plant are its whorls of 4-6 leaves which are very finely divided into needle-like segments resembling tiny fir trees. The leaves are 0.5 to 2 inches long. Leaves above the surface are divided into 6-18 segments; below the surface they are divided into 20-30 segments. The emergent part of the stem is bright green and can extend as much as a foot above the water. The plant’s miniscule flowers are located in stem axils. In the United States, the plant has only produced female flowers.

Reproductive/Dispersal Methods

Stem fragments develop into new plants which are dispersed by water currents, boats, and animals.

Similar Species

Eurasian milfoil (Myriophyllum spicatum), another aquatic invasive species, is similar in appearance, but the emergent stems of the two species are quite different. In Eurasian milfoil, the above-surface part of the stem is reddish and only has small bracts (not leaves) in stem axils. The above-surface stem of parrot feather is bluish green and has numerous whorls of rigid, fir-like leaves (described above).

Impacts

Parrot feather can form dense mats that crowd out native flora and alter water chemistry. It can also interfere with recreational activities like fishing, swimming, and boating.

Distribution

Parrot feather has become naturalized in most of the southern and central United States. It is known from several locations in Connecticut, and there is a report of an infestation on Cape Cod. Its popularity as an aquarium and water garden plant has facilitated its spread.

Sources and Links

Invasive Plant Atlas of New England (IPANE):

http://nbii-nin.ciesin.columbia.edu/ipane/icat/catalogOfSpecies.do

State of WA Dept. of Ecology: Non-native Invasive Freshwater Plants

http://www.ecy.wa.gov/programs/wq/plants/weeds/aqua003.html

MA DCR: Potential Invader: Parrot Feather, an Invasive Aquatic Plant

http://www.mass.gov/dcr/waterSupply/lakepond/factsheet/Parrot%20Feather.pdf