Eurasiain Water Milfoil (Myriophyllum spicatum)

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Eurasian water-milfoil is a submersed, rooted, perennial. Eurasian water-milfoil stems are reddish-brown to whitish-pink. They are branched and commonly grow to lengths of 2-3 m. The leaves are deeply divided, soft and feather-like. Leaves are about 2.5 cm long. The leaves are arranged in whorls of 3 to 6 leaves around the stem. The flowers of Eurasian water-milfoil are reddish and very small. They are held above the water on an emersed flower spike that is several inches long.
Key Identifiers
  • Long stringy stems that branch near water surface
  • 3-5 feathery leaves arranged in whorls
  • Each leaf with 12-21 leaflet pairs
  • Small reddish flowers above the water in mid summer

Chris Evans, River to River CWMA,

Richard Old, XID Services, Inc.,
Location in Canada
Eurasian water-milfoil is present in most U.S. states and in British Columbia, Ontario and Quebec.

BIOLOGY OF CANADIAN WEEDS. 34. Myriophyllum spicatum
Center for Aquatic and Invasive Plants, University of Florida Eurasian Water Milfoil

Similar species
Myriophyllum spicatum might be confused with two native water-milfoils and other submersed plants. Native Myriophyllum sp. generally have less dissected leaves (<12 leaflet pairs). Branches at water surface are sparse in water more than 1 m deep. Turions, a specialized overwintering bud, are present on natives.

Hornwort (Ceratophyllum demersum)- leaves are toothed and the plant feels rough when pulled through the hand, whereas Eurasian water-milfoil leaves are not toothed and the plant does not feel rough

Bladderworts (Utricularia sp.) can also be mistaken for Eurasian watermilfoil, but they are easily distinguished by the presence of many small bladders on the leaves, which serve to trap and digest small aquatic insects.
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This document is maintained by Shelley Barkley.
This information published to the web on June 9, 2012.
Last Reviewed/Revised on February 26, 2018.