Spartina alterniflora x S. foliosa
Common names: smooth hybrid cordgrass
Spartina alterniflora (and S. alterniflora x foliosa hybrids) (smooth cordgrass) is a rhizomatous perennial grass (family Poaceae) found in salt marshes and mudflats in the San Francisco Estuary and associated waterways. Smooth cordgrass spreads more rapidly, grows more densely, and tolerates higher water levels than native California cordgrass (Spartina foliosa). Spartina alterniflora is native to the Atlantic and Gulf coasts of North America. The two cordgrasses are known to hybridize, a process which may threaten the survival of pure strains of California cordgrass. A single smooth cordgrass plant may spread clonally in concentric circles to become a dense circular patch of up to 20 meters in diameter. The invasive cordgrass does not provide suitable habitat for native salt marsh shorebirds.Cal-IPC Rating: High?
CDFA Rating: -*?
Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
Weed Management Notes
- Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.
Cal-IPC Newsletter Articles
- Hybrid Spartina Forum: Defining eradication for a genetic invader. Hogle, Ingrid. Vol 19, Issue 1
- “Conservation Across Borders” in San Jose. Cal-IPC. Vol 14, Issue 2
- Cordgrass and clapper rails. Grijalva, Erik; Kerr, Drew; Zaremba, Katy. Vol 13, Issue 4
- Invasive Spartina: “Just another weed”: Biology, spread, and prospects for control. Richardson, Brianna. Vol 11, Issue 3
Cal-IPC Symposium Presentations
Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.
- Regional partnership to steward San Francisco Bay wetlands. Kerr, Drew (2023)
- California Update. Johnson, Doug (2020)
- Economic impact of selected invasive species: direct costs estimates and economic impacts for Washington State. Haubrich, Greg (2018)
- Washington state’s noxious weed program. Haubrich, Greg (2018)
- Techniques for ecological restoration of Spartina foliosa following local eradication of invasive Spartina alterniflora hybrids. Thornton, Whitney (2014)
- The “other” invasive Spartina in San Francisco Bay: progress towards eradication for the lesser-known species. Kerr, Drew (2014)
- Invasive Spartina Project at a turning point: Eradication on the horizon, reconciling clapper rail impacts, and charting a course towards tidal marsh revegetation with native cordgrass. Kerr, Drew (2011)
- Monitoring a declining, hybridizing weed (7.5 MB). Hogle, Ingrid (2008)
- Self-fertilizing cordgrass hybrids (Spartina alterniflora x S. foliosa) drive local invasion of San Francisco Bay tidal flats. Sloop, Christina M.; Ayres, Debra R.; Strong, Donald R. (2006)
- 2003 Invasive Spartina Project Monitoring Program. Zaremba, K.; McGowan, M.; Ayres, D.R. (2004)
- Behavioral responses of birds to invasive spartina in San Francisco Bay salt marshes. Nordby, J. Cully; Cohen, Andrew N.; Beissinger, Steven R. (2004)
- Invasive hybrid cordgrass (Spartina alterniflora x S. foliosa) recruitment dynamics in open mudflats of San Francisco Bay. Sloop, Christina M.; Ayres, Debra R.; Strong, Donald R. (2004)
- Introduced Spartina in San Francisco Bay: 2000-2001 Survey and Findings, San Francisco Estuary Invasive Spartina Project. Smith, Debra; Klohr, Shannon; Zaremba, Katy (2002)
- Spread of exotic cordgrasses and hybrids (Spartina sp.) in the tidal marshes of San Francisco Bay. Ayres, Debra R.; Smith, Debra L.; Zaremba, Katy; Klohr, Shannon; Strong, Donald R. (2002)
Other Spartina alterniflora x S. foliosa Information
- CalPhotos - Images of plants taken mostly in California.
- Calflora - Distribution map and records of this species in California.
- EDDMapS - Distribution of this species in North America.
- Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
- USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.