Myriophyllum aquaticum (Vell.) Verdc.
Myriophyllum aquaticum (Vell.) Verdc.Brazilian Watermilfoil, Parrot Feather
| Threat Level |
Category |
| Established |
Aquatic |
Description
Stems
Stems and submerged leaves may be reddish tinted; gray-green tips of the stems with leaves may protrude above the water. Stems may be up to 1.5 m long, trailing along the ground or water surface, then becoming erect and leafy at the ends.
Leaves
Leaves are oblong, deeply cut, and feathery-looking. Leaf color is bright blue-green. Parrot-feather leaves are arranged in whorls about the stem. Leaves can be both submerged (1.5 to 3 cm long with 20 to 30 divisions per leaf) and emergent (2 to 5 cm with 6 to18 divisions per leaf). The emergent leaves are stiffer and darker than the submergent leaves.
Flowers
Flowers are inconspicuous (1 to 2 mm long) and white in axils of emergent leaves. Flowers do not produce seeds, as all plants found in the United States have proven to be male.
Images
Photo: Richard Old, XID Services, Inc., Bugwood.org
More images of Myriophyllum aquaticumLife History
Parrot-feather is an aquatic plant with stout elongate stems suspended in the water or floating. Commonly sold for aquaria and aquatic gardens, it has escaped to become invasive in ponds and other calm water bodies. Parrot-feather can form dense mats in waterways, shading out native vegetation and algae.
Habitat
Parrot-feather is limited to non-tidal, freshwater, slow-moving water bodies such as tributaries, ponds, lakes and canals. It favors good light, slightly alkaline and high-nutrient environments.
Origin and Distribution
Parrot-feather is a native of Brazil, found growing in the Amazon River. Parrot-feather occurs in at least 26 states throughout the United States.
Management Recommendations
Mechanical Control
Attempting control by manual or mechanical means tends to spread the plants and should only be conducted in small, contained water bodies.
Chemical Control
Control with herbicides is difficult because the emergent stems and leaves have a waxy cuticle that repels herbicides. 2,4 D, diquat, endothall and glyphosate with surfactants can be used on plants in Summer or Fall. Repeated treatments are necessary.
Biological Control
Research into biological control of parrot-feather is ongoing.
