California Invasive Plant Council

Lepidium draba

Synonyms: Cardaria draba

Common names: heart-podded hoary cress, whitetop

Lepidium draba (hoary cress) is a perennial herb (family Brassicaceae) found most commonly in riparian areas and marshes of the central coast of California. It is also found in the southwestern region of the state, the Sacramento Valley, and the Klamath Range, where it is very invasive. This plant quickly colonizes disturbed sites, irrigated agricultural fields, roadsides and ditches. Hoary cress reproduces by seed and vegetatively from its extensive root system. Plants may resprout from small root fragments, especially where the soil is moist. Hoary cress also spreads rapidly due to its prolific seed production, but extensive control efforts have decreased the rate of spread in recent years.

Cal-IPC Rating: Moderate?

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.

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

• Jepson Manual 2nd ed. invasive plant name changes. Brusati, Elizabeth. Vol 20, Issue 2
• An island called Santa Cruz: Removing invasives on the Channel Islands. Owen, Ken. Vol 12, Issue 2
• Legendary stewardship award. Goode, Suzanne. Vol 06, Issue 2
• Lepidium latifolium L. in California. Young, James A.; Turner, Charles. Vol 03, Issue 1
• California Exotic Pest Plant Council draft list exotic plants of greatest concern October 1993. CalEPPC. Vol 01, Issue 4

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.

• 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)
• Preventing weed spread via contaminated hay and straw. Clines, Joanna (2005)
• Ecology and control of perennial pepperweed (Lepidium latifolium L.). Young, James A.; Palmquist, Debra; Blank, Robert S.; Turner, Charles E. (1995)

Other Lepidium draba 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.

Additional photos