Perennial pepperweed

Lepidium latifolium

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  • Smooth, green-grayish leaves.
  • Up to over 6 feet high, typically 3 to 4 feet.
  • Dense aggregations of tiny white flowers (< 1/4 in.).
  • Has horizontal underground stem (rhizome), which can be viewed by uprooting a plant.

Identification key in: Hickman, J. ed. 1993. The Jepson Manual: Higher Plants of California. University of California Press.

Growth and spread

  • Can reproduce from pieces of underground stems, or by seed.

Habitat and local distribution

  • Can establish dense colonies in a wide variety of environments, including marshes, meadows, saline soils, riparian areas, beaches, and disturbed areas such as roadsides, agricultural fields and irrigation channels.
  • Native of Eurasia. Arrived at the East Coast of the US about 1924. In 1941 the plant was present in Solano county, and in subsequent years has spread to all 9 Bay Area counties. Present in large quantities in the South Bay and Delta, and in limited amounts in the Central Bay (May 1995).


  • Can grow in dense linear patches along sloughs and levees to the exclusion of all other vegetation; able to displace native pickleweed and other native species.

Prevention and Control


  • Plant natives or spread native seed in disturbed areas.

Manual or mechanical control

  • Mechanical methods such as disking do not provide control alone since plants can rapidly resprout from fragments left in soil (Young et al. 1995).
  • Prescribed burning—not effective method of control alone; typical infestations may not be able to maintain burning (Howald 2000).
  • Flooding—may be successful if area is flooded for a prolonged period of time; plant abundance reduced at West Navy Marsh (Contra Costa County) when tidal action returned to diked marsh (May 1995).

Biological control

  • Biological control agents—testing of biological agents not a likely control method due to the risk posed to commercial crop plants in the mustard family (Brassicaceae) and native Lepidium species (Young et al. 1995).

Chemical control

  • Application of herbicides—chlorsulfuron, triclopyr (as Garlon3A® and Garlon4®), and glyphosate (as Rodeo® and Roundup®) have shown to be effective in controlling perennial pepperweed in studies at Grizzly Island Wildlife Area in Suisun Marsh (Howald 2000).
  • Estimated costs: costs for materials and application by a contractor are approximately $250 per acre for glyphosate, depending on size of treatment area, scale of treatment, and herbicide dosage. It is recommended to contract a licensed professional for herbicide applications (Gibbons et al. 1999).

References and more information

Gibbons, M.V., M.G. Rosenkranz, H.L. Gibbons, Jr., and M.D. Sytsma. 1999. Guide for Developing Integrated Aquatic Vegetation Management in Oregon. Center for Lakes and Reservoirs, Portland State University, Portland, OR.

Howald, A. 2000. Lepidium latifolium. In Invasive Plants of California Wildlands. Carla C. Bossard, John M. Randall, Marc C. Hoshovsky, Editors. University of California Press. Available at's_Wildlands .

May, Michael. 1995. Lepidium latifolium L. in the San Francisco Estuary. Department of Geography, University of California at Berkeley. Unpublished report. Available from

Young, J.A, C.E. Turner, and L.F. James. 1995. Perennial pepperweed. Rangelands 17:123-123.

Element Stewardship Abstract for Lepidium latifolium L. , perennial pepperweed, tall whitetop . M.J. Renz. 2000. The Nature Conservancy, Wildland Invasive Species Team. Arlington, VA. Available at

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