Eurasian Watermilfoil
Myriophyllum spicatum

Eurasian watermilfoil is a non-native underwater grass with feathery leaves. It grows in quiet fresh and slightly brackish waters throughout the Chesapeake Bay watershed.

This section shows one large critter image at a time. Use the thumbnails that follow to select a specific image to display here.

Eurasian watermilfoil (Myriophyllum spicatum) and other bay grasses grow in the Susquehanna Flats near Havre de Grace, Md., on July 25, 2016. Milfoil is an invasive species introduced to the Chesapeake Bay. (Photo by Will Parson/Chesapeake Bay Program) USAGE REQUEST INFORMATION The Chesapeake Bay Program's photographic archive is available for media and non-commercial use at no charge. To request permission, send an email briefly describing the proposed use to requests@chesapeakebay.net. Please do not attach jpegs. Instead, reference the corresponding Flickr URL of the image. A photo credit mentioning the Chesapeake Bay Program is mandatory. The photograph may not be manipulated in any way or used in any way that suggests approval or endorsement of the Chesapeake Bay Program. Requestors should also respect the publicity rights of individuals photographed, and seek their consent if necessary.

This gallery contains a grid of small thumbnails. Selecting a thumbnail will change the main image in the preceding section.

Appearance

The Eurasian watermilfoil is made up of tough, branching stems that can grow to 8 feet long. They have delicate, feather-like leaves that grow in whorls of 4 to 5 along each stem. Leaves lose their shape when taken out of the water. Spikes of reddish flowers poke above the water’s surface in late summer. The plant has a rooted base.

Reproduction and life cycle

This grass usually reproduces asexually when stem fragments form into new plants. It can also reproduce sexually in late summer, when female flowers are pollinated through the air. They produce nut-like seeds that sink to the bottom. Seeds can remain viable for years.

Did you know?

  • Eurasian watermilfoil provides good habitat for young fish, crabs and invertebrates.
  • This plant was accidentally introduced in the Chesapeake Bay in the early 20th century. By the late 1950s, thick mats of Eurasian watermilfoil covered thousands of acres of the Bay and its rivers. By 1970 these large beds died back, and today the species grows in moderation.
  • It can be confused with coontail. You can distinguish Eurasian watermilfoil by its feathery leaves that lose their shape when taken out of the water.

Sources and additional information

Tags: