Text Size: A  A  A

Common Waterweed

Elodea canadensis

Common waterweed has tiny, narrow leaves along slender, branching stems. (Maryland Department of Natural Resources)
Common waterweed has tiny, narrow leaves along slender, branching stems. (Maryland Department of Natural Resources)

Common waterweed is a bay grass with tiny, narrow leaves along slender, branching stems. It grows in slow-moving fresh waters throughout the Chesapeake Bay watershed.

Appearance:

  • Slender, branching stems
  • Tiny, narrow leaves that are straight or oval-shaped and grow in whorls of three along each stem
  • Whorls become more crowded toward the tip of the stems
  • Leaves have extremely tiny teeth that may only be visible under magnification
  • From July-September, tiny flowers grow on long stalks from a tubular structure at the leaf axil
  • Weak, thread-like root system

Habitat:

  • Grows mostly in slow-moving fresh waters, but occasionally found in brackish waters
  • Often found in areas rich in nutrients and calcium

Range:

  • Found in the upper Chesapeake Bay and freshwater streams and rivers throughout the Bay watershed

Predators:

  • Migratory waterfowl, especially ducks
  • Muskrats and beavers

Reproduction and Life Cycle:

  • Usually reproduces asexually when stem fragments bud and grow into new plants
  • Rarely reproduces sexually because male plants are very uncommon. When sexual reproduction occurs, the plants produce cylindrical capsules that contain several seeds.

Other Facts:

  • Also known as Canadian waterweed
  • Provides good habitat for fish, amphibians and aquatic invertebrates
  • Can be confused with hydrilla. You can distinguish common waterweed by its leaves, which grow in whorls of three and do not have visible teeth.

Sources and Additional Information:

  • Underwater Grasses in Chesapeake Bay & Mid-Atlantic Coastal Waters by Peter W. Bergstrom, Robert F. Murphy, Michael D. Naylor, Ryan C. Davis and Justin T. Reel
  • Life in the Chesapeake Bay by Alice Jane Lippson and Robert L. Lippson
  • Chesapeake Bay: Nature of the Estuary, A Field Guide by Christopher P. White
  • Bay Grass Key: Common Waterweed – Maryland Department of Natural Resources
  • PLANTS Database: Elodea canadensis – USDA Natural Resources Conservation Service

Places:




Click tabs to swap between type and habitat.

410 Severn Avenue / Suite 112
Annapolis, Maryland 21403
Tel: (800) YOUR-BAY / Fax: (410) 267-5777
Directions to the Bay Program Office
Terms of Use | Privacy Policy
©2012 Chesapeake Bay Program | All Rights Reserved