Widgeon Grass
Ruppia maritima

Widgeon grass is an underwater grass with delicate, thread-like leaves that grow alternately along slender, branching stems. It ranges from slightly brackish upper and middle Chesapeake Bay rivers to the saltier lower Bay.

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A view of widgeon grass underwater with a pale background.
Widgeon grass has straight, delicate, thread-like leaves that grow alternately along slender branching stems. (Photo by Will Parson/Chesapeake Bay Program)

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Appearance

Widgeon grass has delicate, thread-like leaves with rounded tips and a sheath at the base. Leaves grow alternately along slender, branching stems. The grass grows in two forms: an upright, branched form with flowers that stand several feet tall, and a short, creeping form with leaves at the base of the plant.

In late summer, long stalks with clusters of individual black, pointed seeds grow from the base of the leaves. Widgeon grass has an extensive root system with creeping rhizomes (underwater portion of a plant's stem) that lack tubers which are a specialzed stem or root organ that stores nurtrients.

Predators

Migratory waterfowl feed on widgeon grass.

Reproduction and life cycle

Widgeon grass reproduces sexually between late spring and late summer when two flowers, which are enclosed in a sheath at the base of the leaves, emerge and grow on a stalk toward the water’s surface.

Pollen floating on the water’s surface fertilizes the flowers, which then produce seeds. It can also reproduce asexually, when new stems grow from the plant’s root and rhizome system.

Did you know?

  • Widgeon grass is also known as ditch grass because it sometimes grows in ditches along road sides and farm fields.
  • This grass can most commonly be found in shallow areas with a sandy bottom, but can also grow in soft, muddy sediments.
  • Migratory waterfowl feed on widgeon grass.
  • It can be confused with sago pondweed, slender pondweed and horned pondweed. Widgeon grass can be distinguished by its leaves, which grow alternately along the branches, and its seeds, which grow on individual stalks.

Sources and additional information

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