Elodea canadensis
Common waterweed, Common Waterweed
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Family: Hydrocharitaceae · Type: Herb · Native
Elodea canadensis (Common waterweed) is a native California herb in the Hydrocharitaceae family, recognized by leaf width, crowding pattern, and hairless seeds.
Common waterweed is a California native perennial found in the Northern Coast Ranges, Central High Cascades, Sierra Nevada, Central Valley, San Francisco Bay Area, Southern California Ranges, and Great Basin in shallow water, sloughs, ponds, and lakes at elevations of 300 to 2,600 meters. Flowering from July to August, this aquatic plant produces delicate white flowers nestled among dense leaf clusters. Growing with slender, flaccid stems that spread through shallow waters, it forms extensive underwater meadows. Its leaves are densely arranged at stem tips, typically three per node, with narrow linear blades 5 to 15 millimeters long and 2 to 5 millimeters wide, tapering to obtuse or abruptly pointed tips. The plant can reproduce vegetatively, creating extensive colonies in quiet water environments.
Identification and appearance
Key characters: 2 sympatric species; distinguished by leaf width, crowding pattern, and hairless seeds
Habitat and range
Habitat: Shallow water, sloughs, ponds, lakes
Elevation: 300-2600 m
Outside California: to British Columbia, eastern United States, naturalized in Europe, Australia
Bloom period
Elodea canadensis blooms Jul-Aug.
How to tell it apart
vs Myriophyllum: Elodea has simple undivided leaves; Myriophyllum leaves are feathery and divided into thread-like segments.; vs Hydrilla: Elodea has smooth leaf midribs; Hydrilla midribs have tiny prickles underneath.; vs Ceratophyllum: Elodea has simple leaves; Ceratophyllum leaves fork repeatedly into stiff thread-like divisions.; vs Najas: Elodea has 2-7 leaves per node depending on position; Najas has opposite or whorled leaves throughout.; vs Egeria: Elodea leaves are tiny (under 1.5 cm); Egeria leaves are much larger (1.2-4 cm long).
Frequently asked questions
Is Elodea canadensis native to California?
Yes. Elodea canadensis is native to California (recorded as native).
When does Elodea canadensis bloom?
Elodea canadensis blooms Jul-Aug.
What plant family does Elodea canadensis belong to?
Elodea canadensis is in the Hydrocharitaceae family, genus Elodea.
What habitat does Elodea canadensis grow in?
Elodea canadensis grows in Shallow water, sloughs, ponds, lakes.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.