Stem simple to freely branched, elongate and flexuous, to 3'-5' long Turions with reduced blackish leaves and shortened internodes often produced from lower nodes in late summer and fall, present through spring. A submerged aquatic plant, identifiable as a milfoil by its finely dissected, thread-like leaves.
Plants often turn whitish when dried.
Boreal North America, south to Maryland, Ohio, Indiana, Texas, New Mexico, and California. Its presence significantly increases the abundance of most groups of macroinvertebrates, including gastropods, amphipods, daphnids, chironomids, ephemeropterans, trichopterans, and odonates - though not so much the copepods and oligochaetes. The value of milfoil to macroinvertebrates is likely due more to its value as habitat than as food. The more aggressive nature of Eurasian milfoil makes it a potential menace in recreational waters. Extreme care should be exercised when boating or fishing in infested waters so as not to inadvertently introduce the plant to uninfested lakes and streams.