California Invasive Plant Council

Spartina densiflora

Common names: dense-flowered cordgrass; Chilean cordgrass.

Spartina densiflora (dense-flowered cordgrass) is a rhizomatous perennial grass (family Poaceae) found in salt marshes in Humboldt Bay and San Francisco Bay. Dense-flowered cordgrass may have been introduced to Humboldt Bay from Chile by lumber ships in the 19th century. It tolerates high salinity and grows especially well in higher tidal marsh, where it is known to displace native pickleweed (Salicornia pacifica) and native California cordgrass (Spartina foliosa). The species’ abundant seed has the potential to disperse over long distances by floating on water.

Cal-IPC Rating: High

CDFA Rating: B*

Cal-IPC Assessment

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

• Protecting San Francisco Bay salt marshes from invasive sea lavender. Whitcomb, Amy. Vol 24, Issue 3
• BEYOND THE WAR ON INVASIVE SPECIES: A PERMACULTURE APPROACH TO ECOSYSTEM RESTORATION. Orion, Tao. Vol 24, Issue 3
• 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.

• 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)
• 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)
• Adaptive integrated vegetation management of invasive Spartina densiflora in the San Francisco Estuary. Kerr, Drew (2010)
• Monitoring a declining, hybridizing weed (7.5 MB). Hogle, Ingrid (2008)
• 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 densiflora Information

• CalPhotos - Images of plants taken mostly in California.
• Calflora - See the distribution of this species on Calflora's map of California.
• CalWeedMapper - Distribution information with ability to determine regional priorities.
• Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
• USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.
• EDD MapS - North American distribution based on Early Detection and Distribution Mapping System.