Water Milfoil

Water Milfoil (Myriophyllum spicatum) is an aggressive non-native plant that was probably brought to the U.S. as an aquarium plant. The thick stems are multi-branched, somewhat reddish in color, with gray-greenish leaves. The leaves are in whorls of 3 to 5 around the stem, with each leaf divided into 12 or more pairs of limp, thin, thread-like leaflets that look like small feathers. It forms thick underwater mats that can become topped out at the water's surface.

Water milfoil growing densely at the water's surface  

Management Options

Mechanical Options

Water Milfoil can be controlled through cutting and raking, dyes, fertilizers, or barriers.

Information on mechanical treatment of aquatic vegetation

Biological Options

Grass carp will consume Water Milfoil and are good at controlling it.

Information on biological treatment of aquatic vegetation

Chemical Options

The active ingredients that have been successful in treating Water Milfoil include: 2,4-D (E), Bispyribac Sodium (G), Copper Based (G), Diquat (E), Endothall (E), Flumioxazin (G), Fluridone (G), Imazamox (G), Penoxsulam (E), and Triclopyr (E). E = excellent; G = good.

Information on chemical treatment of aquatic vegetation

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