California Invasive Plant Council

Arundo donax

Common names: giant reed

Arundo donax (giant reed) is a tall perennial grass (family Poaceae) that typically forms dense stands on disturbed sites, sand dunes, riparian areas, and wetlands. It has invaded central and coastal Southern California river valleys, central California river valleys in San Luis Obispo and Monterey counties, the San Francisco Bay Area, the Sacramento and San Joaquin River valleys and is also increasing in the North Coast region. Arundo donax is threatening California’s riparian ecosystems by outcompeting native species, such as willows, reducing the nesting and foraging value of habitat, changing streamflow, and utilizing more water than native vegetation. It is native to northern Africa and western and central Asia.

Cal-IPC Rating: High?

Explanation of Cal-IPC ratings

• High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
• Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
• Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
• Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
• Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.

CDFA Rating: -*?

Explanation of CDFA ratings

• A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
• B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
• C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
• D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
• Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
• * – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
• -* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.

More details

Assessment(s)

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.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Special Reports

• Arundo donax Distribution and Impacts - From 2008-2010, Cal-IPC mapped Arundo donax at high resolution on all coastal watersheds in California from Monterey to San Diego. Impacts from Arundo invasion were calculated over the study area, including impacts to biomass production, water use, fire, geomorphic and fluvial processes, and endangered species.
• Central Valley Arundo Distribution, Impacts, and Management - From 2016-2019, Cal-IPC mapped Arundo donax populations at high resolution across California’s Central Valley, a 38.4 million acre project area that includes the foothills. The project area is broken into 25 watershed units in which we calculate four types of impact (water, geomorphology, fire, sensitive species) based on the amount of Arundo present and other factors. We then integrate the impact for each watershed unit with an assessment of local capacity to build and implement a long-term Arundo removal program. From these integrated factors, we suggest priorities and make management recommendations.

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

• San Ramon Creek's Arundo is on the road to eradication. Anciaux, Mike; Heron, Dick. Vol 32, Issue 1
• Arundo wasp established in Central Valley. Moran, Patrick. Vol 28, Issue 3
• Are we making progress? A bird's-eye view of change in invasive plant cover in central-coastal Orange County. Burger, Jutta C.. Vol 27, Issue 2
• Invasive plant species mapping in the Santa Ana River Watershed. Seferyn, Sloane. Vol 27, Issue 2
• Wildfire helps Arundo control at Hansen Dam basin. Neill, Bill. Vol 27, Issue 1
• Mapping Arundo (giant reed) across the Central Valley. Morawitz, Dana. Vol 26, Issue 2
• Wildland Weeds News. Cal-IPC. Vol 26, Issue 1
• Snapshots from the field. Lindgren, Jackie; Eberwein, Amy; Parish, Julie; Chapple, Tanya. Vol 26, Issue 1
• Symposium tool sampler. Schohr, Tracy; Williams, Andrea; Norelli, Nicole; Newhouser, Mark. Vol 25, Issue 3
• Wildland Weed News. Cal-IPC. Vol 25, Issue 1
• Eradicating knotweeds and other new invaders on California’s North Coast. Eberwein, Amy. Vol 24, Issue 3
• Wildland Weed News. Cal-IPC. Vol 24, Issue 2
• Canes of Wrath: Farmers and conservationists working together to transform the Salinas River. Segoviano, Ilima; Robins, Paul; Giessow, Jason. Vol 23, Issue 1
• Weed biological control agents approved for California. Pitcairn, Michael J.; Smith, Lincoln; Moran, Patrick. Vol 22, Issue 1
• Taking to the air to locate, prioritize and treat effectively. Burger, Jutta C.. Vol 21, Issue 2
• Wildland weed news. Cal-IPC. Vol 20, Issue 4
• Special concerns near aquatic habitats. Drill, Sabrina; Trumbo, Joel. Vol 20, Issue 4
• Prioritizing Regional Response to Invasive Plants in the Sierra Nevada. Brusati, Elizabeth; Morawitz, Dana; Powell, Cynthia. Vol 19, Issue 2
• Mapping Arundo and its impacts. Giessow, Jason; Casanova, Jason; Leclerc, Rene. Vol 19, Issue 1
• Stopping the unintentional spread of arundo. Boland, John. Vol 18, Issue 2
• Does arundo use more water than a native willow?. Zimmerman, Tricia; Conser, Christiana. Vol 18, Issue 1
• A new invasive raspberry?. Marovich, Rich. Vol 17, Issue 3
• Invasive plant conference in South Africa. Darin, Gina. Vol 17, Issue 3
• The cost of weeds to California. Brusati, Elizabeth. Vol 17, Issue 1
• “We don’t know what we need to know”. Robinson, Ramona. Vol 16, Issue 4
• Using the Arundo hook to bend-and-spray. Newhouser, Mark. Vol 16, Issue 1
• Funding outside the box. Brandt, Laurel. Vol 15, Issue 3
• Weed workers and wildlife biologists find common ground in Monterey. Brusati, Elizabeth. Vol 15, Issue 1
• Shasta County citizens take on weeds. Dozier, Melissa. Vol 14, Issue 4
• Seed production in Arundo donax?. Johnson, Maile; Dudley, Tom; Burns, Casey. Vol 14, Issue 3
• Low-volumn foliar treatment of Arundo using imazapyr. Neill, Bill; Angeles, Team Arundo. Vol 14, Issue 1
• Conservation Corps attacks Arundo. Griffith, John; Hill, Kristin. Vol 13, Issue 4
• Don’t sell a pest: A new partnership to prevent plant invasions through horticulture. Connick, Sarah; Gerel, Mike. Vol 13, Issue 2
• Which weeds dominate southern California urban riparian systems?. Burkhart, Brad; Kelly, Mike. Vol 13, Issue 1
• Setting the stage: The Ventura County Arundo Task Force. Rose, Peggy. Vol 12, Issue 2
• New remote sensing tool under evaluation. Horney, Marc. Vol 10, Issue 4
• Exotic pest plants, Calif. Assoc. of Nurserymen, and CalEPPC. Bell, Carl E.; Evans, Mike; Wilen, Cheryl. Vol 09, Issue 1
• Foreign exploration for biological control of Arundo donax. Dudley, Tm. Vol 08, Issue 4
• Education: Wildland weed tours and talks. Kelly, Mike. Vol 08, Issue 1
• Roundup of Arundo projects reveals commitment, strategic weakness. Kelly, Mike. Vol 07, Issue 2
• Results of the CalEPPC questionnaire at Symposium ’98 in Ontario. DiTomaso, Joe. Vol 06, Issue 4
• The weed from hell arrives in paradise. Starkey, Frank. Vol 06, Issue 4
• Legendary stewardship award. Goode, Suzanne. Vol 06, Issue 2
• CalEPPC Symposium ’97. Warner, Peter. Vol 06, Issue 1
• The weed from hell finds a buyer. Sims, Ted. Vol 05, Issue 4
• Killing the beast: A cooperative approach for control of Arundo donax in the Santa Ana River watershed. Stein, Eric D.; Vartanian, Valerie. Vol 05, Issue 3
• Lessons from the front: Taking stock to avoid surprises. Kelly, Mike. Vol 05, Issue 1
• Effects of Arundo donax on water resources. Iverson, Mark E.. Vol 03, Issue 1
• Exotic pest plants of greatest ecological concern in California September 1994. Cal-IPC. Vol 02, Issue 4
• Tamarisk advancing in Baja California. Kelly, Mike. Vol 02, Issue 3
• California Exotic Pest Plant Council draft list exotic plants of greatest concern October 1993. CalEPPC. Vol 01, Issue 4
• Working group reports on weed control methods and applications for Arundo, french broom, german ivy, hoary cress, yellow starthistle, and pampasgrass. Cal-IPC. Vol 01, Issue 3
• The story of Team Arundo. Jackson, Nelroy. Vol 01, Issue 2

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.

• Biological control agents of weeds in California: Overview of rearing, releases, and monitoring by the CDFA Biological Control Program. Moran, Patrick (2023)
• Biological control of aquatic weeds in California: Status update and a look to the future. Pratt, Paul (2023)
• Manipulation of release conditions improves establishment of the wasp Tetremesa romana for biological control of Arundo in northern California. Moran, Patrick (2023)
• Techniques to eradicate giant reed from Trabuco Creek, Orange County. Freese, Robert; Raff, Collin (2023)
• Habitat restoration at Hidden Valley Wildlife Area following long-term Arundo management. Conser, Christiana (2022)
• Mapping, Control, and Monitoring Arundo donax in San Ramon Creek. Anciaux, Mike (2022)
• Update on recent biological control releases against invasive plants by the USDA-ARS. Moran, Patrick; Pratt, Paul; Smith, Lincoln (2022)
• Avian responses to Arundo removal and restoration. Carey, Sean; Hall, Linnea; Kisner, David; Lambert, Adam; Braman, Charlie (2021)
• Giant Reed (Arundo donax) control on the San Luis Rey River Watershed from 2000 to 2021: Persistence, perspective and patience (transformation, but still on the wheel). Giessow, Jason (2021)
• Identifying native plants that promote riparian insect community recovery after giant reed (Arundo donax) removal: Ant community composition. Braman, Charlie; Lambert, Adam (2021)
• Leveraging partnerships to advance giant reed (Arundo donax) removal and restoration in the Santa Clara River. Lambert, Adam (2021)
• North Coast invasive weeds: Early detection rapid response eradication project. Ferson, Susannah; Avila-Martinez, Carla (2021)
• Pollinator response to giant reed (Arundo donax) removal in a Southern California riparian system. Hobson, Evan (2021)
• Biological control of Arundo donax with the arundo wasp in the Central Valley. Moran, Patrick; Bitume, Ellyn; Rogers, D. Valle (2020)
• California Update. Johnson, Doug (2020)
• Invasive plant species mapping using drones in the Santa Ana River watershed. Fox, A.J. (2019)
• Partnering with California Conservation Corps on large scale weed removal in the Oroville Wildlife Area. Ferrara, Holly (2019)
• Biological control of Arundo donax. Bitume, Ellyn; Moran, Patrick (2018)
• Recent research on invasive weeds at the European Biological Control Laboratory (EBCL). Smith, Lincoln; Bon, Marie-Claude; Desurmont, Gaylord; Kashefi, Javid; Sforza, René; Tannières, Mélanie; Cristofaro, Massimo; Marini, Francesca; Goolsby, John; Rector, Brian; Vidovic, Biljana; Winkler, Daniel; Moran, Patrick (2018)
• Aerial lifts and Arundo donax control in the Sacramento-San Joaquin Delta. Newhouser, Mark (2017)
• Mapping, prioritization, and eradication of Arundo donax in the Sacramento-San Joaquin Delta. Young, Alex (2017)
• New biocontrol releases and integrated control targeting Arundo in riparian areas. Bitume, Ellyn (2017)
• Designing wildlife avoidance into invasive species control projects. Austin, Rick L. (2011)
• Distribution and impacts of Arundo donax from Monterey to Tijuana. Giessow, Jason; Casanova, Jason; Leclerc, Rene (2011)
• How does light attenuation affect giant reed (Arundo donax) establishment? Palenscar, Kai; Holt, Jodie S. (2011)
• The evolution of arundo removal efforts on Camp Pendleton. Lardiere, Benjamin M.; Bieber., Deborah (2011)
• Strategic planning for control of Arundo donax and restoration of riparian vegetation in semi-arid landscapes: a case study from the lower Santa Clara River, CA. Orr, Bruce K.; Diggory, Zooey; Dudley, Tom (2010)
• The Matilija Dam Ecosystem Restoration Project. Reinoehl, Steven; Zaich, Craig (2010)
• Maintaining riparian habitats after initial invasive plant treatments on Camp Pendleton. Lardiere, Benjamin M.; Bieber, Deborah (2009)
• Mapping weeds from the ground, the air or beyond. Griswold, Margot; Williams, Dane; Schmid, Brian; Robinson, Rob (2009)
• Soil moisture stress tolerance of a leading biofuel crop Miscanthus x giganteus is similar to the invasive weed Arundo donax. Mann, Jeremiah; Barney, Jacob; Kyser, Guy; DiTomaso, Joe (2009)
• Team Arundo del Norte: Lessons learned from a coordinated approach to weed management. Newhouser, Mark; DiPietro, Deanne; Spencer, David; Unger, Ron; Sesser, Bryan; Stewart, Zhahai (2009)
• Eradicating 25 species- Challenges and successes of switching from population to seed bank management on Catalina Island, California. Knapp, John; Ratay, Sarah; Hall, Jon (2007)
• How to develop user-friendly riparian corridor invasive exotic species/habitat restoration master plans: Experiences on the San Diego and Otay Rivers. Burkhart, Brad; Kelly, Mike (2007)
• The Break-up and Dispersal of Arundo donax by Bulldozers. Boland, John (2007)
• Wildly successful restoration & mitigation: A contractors perspective. Caruana, John; LaMond, Lisa; Caruana, Michelle (2007)
• Layering: A ‘new’ mode of spread in Arundo donax. Boland, John (2006)
• Potential for augmentation biological control of Arundo donax. Lambert, Adam; Dudley, Tom (2006)
• Team Arundo del Norte’s arundo eradication and coordination program, a regional approach: Uniting weed management and research through interlinking adaptive management feedback loops. Newhouser, Mark; Spencer, David; Unger, Ron; DiPietro, Deanne (2006)
• The proliferation of Arundo donax in Arroyo Las Posas. Huber, Anna-Maria (2006)
• Upper Santa Clara River arundo/ tamarisk removal plan. Cabanting, Noreen (2006)
• Are we creating the ideal conditions for Arundo donax invasion in California? Coffman, Gretchen C.; Dudley, Tom; Rundel, Phil W.; Ambrose, Richard F. (2005)
• Invasive plant control at California State Parks in the northern Sacramento Valley. Dempsey, Jim; Elliott, Woody (2005)
• Effects of environment on establishment of Arundo donax in three southern California riparian areas. Quinn, Lauren; Holt, Jodie S. (2004)
• Funding invasive plant projects through the farm bill. Warner, John (2004)
• Invasion of Arundo donax in riparian ecosystems of Mediterranean-type climates: Causes, impacts and management strategies. Coffman, G.C. (2004)
• Mapping working group. Schoenig, Steve; DiPietro, Deanne; Newhouser, Mark (2004)
• Partnering to prevent invasions of plants of horticultural origin. Connick, Sarah; Gerel, Mike (2004)
• Riparian working group. Giessow, Jason; Newhowser, Mark (2004)
• The riparian weed management program at Marine Corps Base Camp Pendleton: Past, present, and future. Fitch, Meghan Trainor; Bieber, Deborah (2004)
• A watershed approach to Arundo donax removal and riparian restoration. Gaffney, Karen (2003)
• Biocontrols: Progress and ongoing needs. Carruthers, Ray; Buettner, Joel (2003)
• Invasibility of experimental riparian communities by Arundo donax. Quinn, Lauren; Holt, Jodie (2003)
• Seasonal activity and impacts of Arundo donax. Rauterkus, Michael; Holt, Jodie (2003)
• Influences of Arundo donax invasion on riparian biodiversity. DiPietro, Deanne; Dudley, Tom (2002)
• Predicting Arundo donax shoot emergence using degree-day based equations. Spencer, David F.; Ksander, Gregory G. (2002)
• Regulatory compliance at the county level. Rose, Peggy (2002)
• Exotic plants in the Sonoran desert region, Arizona and Sonora. Devender, Thomas R. Van; Frlger, Richard S.; M., Alberto Burquez (1997)
• Formation of “Team Arundo del Norte” in northern and central California. Jones, Paul A. (1997)
• Post flood establishment of native woody species and Arundo donax. Else, Jesse A. (1996)
• Teamwork kills Arundo in cost-effective manner. Lawson, D.M.; Vartanian, V.; Else, L..A. (1996)
• Overview of extension non-crop weed research in California. DiTomaso, Joe (1995)

Other Arundo donax Information

• Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
• CalPhotos - Images of plants taken mostly in California.
• Calflora - Distribution map and records of this species in California.
• CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
• 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.

Additional photos