Family: Haloragaceae (Water-Milfoil Family)
Duration and Habit: Perennial Herb
Aquatic plant with stout stems; both stems and submerged leaves may be reddish tinted; gray-green tips of the stems with leaves may protrude above the water. Leaves are finely divided, pale whitish green in color, in whorls of mostly five with smooth leaf margins. Flowers in axils of emerged leaves; fruits up to 1/8 inch long.
Ecological Threat: Parrotfeather can form dense mats and compete with native aquatic plants, especially in shallow ponds. It also provides habitat for mosquito larvae, impedes boats and clogs drainage ditches.
Biology & Spread: Spreads vegetatively from whole plants or fragments; it can be dispersed by people dumping aquaria into rivers and ponds and by animals carrying fruits and fragments on their bodies.
History: Parrotfeather was introduced to the United States in the Washington, DC area about 1890. Commonly sold for aquaria and aquatic gardens, it has escaped to some freshwater ponds in this region.
U.S. Habitat: Parrotfeather is limited to non-tidal fresh waters.
U.S. Nativity: Introduced to U.S.
Native Origin: Brazil, Argentina, Chile (NatureServe Explorer)
U.S. Present: AL, AR, AZ, CA, CT, FL, GA, HI, ID, KS, KY, LA, MO, MS, NC, NJ, NY, OH, OK, OR, PA, SC, TN, TX, VA, WA
Distribution: Parrotfeather occurs in at least 26 states throughout the United States.
List All Observations of Myriophyllum aquaticum reported by Citizen Scientists
Looks likes coontail (Ceratophyllum demersum), hydrilla (Hydrilla verticillata, non-native, invasive), Eurasian watermilfoil (Myriophyllum spicatum, non-native, invasive), and possibly elodeas.
Attempting control by manual or mechanical means tends to spread the plants and should only be conducted in small, contained water bodies. Draining a pond in the summer achieved control in one instance, but draining may not achieve control in winter. Control with herbicides is difficult because the emergent stems and leaves have a waxy cuticle that repels herbicides. Research into biological control of parrotfeather is ongoing.USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service, 82 pp.
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Invasive Plant Atlas of the United States: Myriophyllum aquaticum
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