California Invasive Plant Council

Lepidium latifolium

Synonyms: Cardaria latifolia (L.) Spach

Common names: perennial pepperweed; tall whitetop; broadleaved pepperweed

Lepidium latifolium (perennial pepperweed, tall whitetop) is a perennial herb (family Brassicaceae) that is native to Eurasia and found in moist or seasonally wet sites throughout California. Perennial pepperweed grows very aggressively, forming dense colonies that exclude native species. It reproduces both by seed and vegetatively from its roots and small root fragments. Seeds and root fragments are spread easily by flooding and soil movement, and seeds stick to tires, shoes, and animals, making continued dispersion difficult to avoid. Perennial pepperweed also increases soil salinity, reducing germination of many desirable species. It is a state-listed noxious weed in California and many other western states.

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

• Pest Notes on Perennial Pepperweed - from the University of California's Statewide Integrated Pest Management Program
• Biology, Ecology and Control of Perennial Pepperweed - Dissertation from UC Davis Weed Research & Information Center
• Perennial Pepperweed Brochure - from the UC Davis Weed Research & Information Center

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

• Controlling invasive plants with a spray drone. Takekawa, John Y., PhD, Operations Manager; Edmunds, Tim, Biologist, Suisun RCD. Vol 28, Issue 1
• Snapshots from the field. Lindgren, Jackie; Eberwein, Amy; Parish, Julie; Chapple, Tanya. Vol 26, Issue 1
• Weeds and climate resilience in Sierra meadows. Brusati, Elizabeth; Johnson, Doug. Vol 24, Issue 1
• Tracking eradication progress . Guise, Vince. Vol 21, Issue 3
• Perennial pepperweed control decision guide. Whitcraft, Christine. Vol 19, Issue 3
• Perennial pepperweed control in riparian areas. Bell, Carl. Vol 18, Issue 3
• East Bay volunteers head to the hills and the shores. Schwartz, Susan. Vol 16, Issue 4
• “Dip-and clip”: A new treatment for herbaceous weeds. Erskine Ogden, Jennifer A.; Renz, Mark; Donaldson, Sue. Vol 14, Issue 4
• Invasive Spartina: “Just another weed”: Biology, spread, and prospects for control. Richardson, Brianna. Vol 11, Issue 3
• Fighting weeds in the Tahoe basin. Donaldson, Sue. Vol 11, Issue 2
• New remote sensing tool under evaluation. Horney, Marc. Vol 10, Issue 4
• 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
• Lepidium latifolium L. in California. Young, James A.; Turner, Charles. Vol 03, Issue 1
• Perennial pepperweed: A threat to wildland areas. Trumbo, Joel. Vol 02, 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.

• Big Canyon Habitat Restoration and Resiliency Project Phase 3: CEQA exempt through CDFW’s SERP process. Arenas, Alys (2023)
• Evaluating the plasticity of a “specialized” rodent in a highly-invaded estuary. Smith, Katie (2023)
• Cross-county collaboration on weed management for success on Delta habitat restorations. Davis, Elizabeth; Weise, Ben; Williams, Amy (2022)
• Case study: The mystery of perennial pepperweed and chlorsulfuron in Sierra Valley. Getts, Tom (2021)
• Laws and regulations that inform noxious weed treatments. Mila, LeeAnne (2020)
• The sky is not the limit – controlling invasive plants with survey and spray drones. Takekawa, John; Edmunds, Tim; Reynolds, Bill; Potter, Chris; Chappell, Steven (2020)
• Two years after the fire: accomplishments in invasive plant control following the 2018 Woolsey Fire. Algiers, Joey (2020)
• Using detection dogs to enhance invasive plant management strategies. Hurt, Aimee (2020)
• Weeds after Woolsey. Algiers, Joseph (2019)
• Maintaining riparian habitats after initial invasive plant treatments on Camp Pendleton. Lardiere, Benjamin M.; Bieber, Deborah (2009)
• Ecological remote sensing of invasion by perennial pepperweed (7.2 MB). Andrew, Margaret E.; Ustin, Susan L. (2008)
• Perennial pepperweed (Lepidium latifolium) control in tidal marsh of San Pablo Bay (1.9 MB). Block, Giselle; Hogle, Ingrid; Spenst, Renee (2008)
• Assessing non-target vegetation response in the wake of perennial pepperweed (Lepidium latifolium) eradication at the Cosumnes River Preserve. Hutchinson, Rachel A.; Viers, Joshua H.; Quinn, James F. (2007)
• Coyote Creek floodplain reclamation project: Re-establishing native plant habitat. Codianne, Jennifer; Dumont, Leo (2007)
• Distributional patterns of perennial pepperweed (Lepidium latifolium) in the San Francisco Bay, a CalFed project. Vanderhoof, Melanie; Rogers, Chris (2007)
• Managing herbaceous perennials in the Tahoe Basin. Erskine Ogden, Jennifer A.; Renz, Mark J.; Norsworthy, Justin; Donaldson, Sue (2007)
• Integrated management strategies for perennial pepperweed. Wilson, Rob; DiTomaso, Joseph; Boelk, Debra; Kyser, Guy (2006)
• Invasive plant monitoring using volunteers: A nationwide effort. Block, Giselle; Hogle, Ingrid; Spenst, Renee; Leininger, Samuel (2006)
• Is glyphosate a good choice for perennial pepperweed (Lepidium latifolium) control in tidal wetlands in the San Francisco Estuary? Spenst, Renee; Foin, T.C. (2006)
• Tall whitetop control on the 102 Ranch and implications for other applications. Etra, Julie (2006)
• Water, salt, and pepper: Lepidium latifolium invasion potential along a salinity and moisture gradient. Leininger, Samuel; Foin, T.C. (2006)
• Efficacy and safety of new herbicides on the horizon. DiTomaso, Joseph M. (2005)
• Perennial pepperweed control experiment at the Cosumnes River Preserve. Hogle, Ingrid B.; Waegell, Rebecca (2005)
• Suppressing exotic weeds on restoration projects using an aggressive herbaceous understory. Sperber, Tamara; Griggs, F.T. (2005)
• Distribution of perennial pepperweed in Bay-Delta wetlands: a CalFed mapping project. Rogers, Chris (2004)
• Fire working group. Clines, Joanna; DiTomaso, Joe; Goode, Suzanne (2004)
• Floodplain invasion: Tracking pepperweed expansion in the Cosumnes River. Hogle, I.H.; Viers, J.H.; Quinn, J.F.; Schwartz, M.W. (2004)
• Invasion dynamics of perennial pepperweed along the salinity gradient. Spenst, R.O.; Foin, T.C.; Miles, A.K. (2004)
• Mapping working group. Schoenig, Steve; DiPietro, Deanne; Newhouser, Mark (2004)
• Riparian working group. Giessow, Jason; Newhowser, Mark (2004)
• Towards eradication of Lepidium latifolium at Paramount Ranch: Control methods and a test of restoration treatments. Brigham, Christy (2004)
• Biocontrols: Progress and ongoing needs. Carruthers, Ray; Buettner, Joel (2003)
• Getting the job done: Working within the regulatory environment at Lake Tahoe to manage weeds. Donaldson, Susan; West, Wendy; Taylor, Kirk (2003)
• Perennial pepperweed: What works? Wilson, Rob (2003)
• Tall whitetop eradication and native plant community restoration. Peters, Shannon; Etra, Julie; Wright, Karen (2003)
• Flood-borne noxious weeds: Impacts on riparian areas and wetlands. Donaldson, Susan G. (1997)
• Risk analysis of various weed control methods. DiTomaso, Joseph M. (1997)
• Ecology and control of perennial pepperweed (Lepidium latifolium L.). Young, James A.; Palmquist, Debra; Blank, Robert S.; Turner, Charles E. (1995)
• Overview of extension non-crop weed research in California. DiTomaso, Joe (1995)

Other Lepidium latifolium 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