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National Invasive Species Information Center
U.S. Department of Agriculture
Home / Terrestrial Invasives / Terrestrial Plants / Whitetop

Whitetop

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Whitetop (hoary cress)
Hoary cress (whitetop) - Photo by Steve Dewey; Utah State University
Scientific Name: 
Lepidium draba L. Desv. (formerly known as Cardaria draba) (ITIS)
Common Name: 
Whitetop, hoary cress, whiteweed, peppergrass, heart-podded hoarycress, hoary cardaria
Native To: 
Eurasia (Zouhar 2004)
Date of U.S. Introduction: 
1800s (Zouhar 2004)
Means of Introduction: 
Possibly introduced as an ornamental (Zouhar 2004)
Impact: 
Crowds out native species and reduces crop yields (Zouhar 2004)

Distribution / Maps / Survey Status

Early Detection & Distribution Mapping System (EDDMapS) - Hoary Cress
University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.
Pest Tracker - Survey Status of Hoary Cress; Whitetop
USDA. APHIS. Cooperative Agricultural Pest Survey. National Agricultural Pest Information System.

Images

Google Images - Hoary Cress
Google.
Invasive.org - Hoary Cress
University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

YouTube - How to Control Whitetop Weed

Google. YouTube; Utah State University Extension.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Whitetop.

Council or Task Force
Fact Sheet: Hoary Cress (Jan 2014) (PDF | 983 KB)

Alberta Invasive Species Council (Canada).

See also: Fact Sheets for more information about individual invasive species, including those listed as "Prohibited Noxious" and "Noxious" under the Alberta Weed Control Act

Invasive Plants of California's Wildlands - Cardaria draba

California Invasive Plant Council.

In online book: Bossard, C.C., J.M. Randall, and M.C. Hoshovsky (Editors). 2000. Invasive Plants of California's Wildlands. University of California Press. Berkeley, CA
Partnership
Federal Noxious Weed Disseminules of the U.S. - Fact Sheet: Cardaria draba

USDA. APHIS. PPQ. Center for Plant Health Science and Technology; California Department of Food and Agriculture.

Hoary Cress Consortium
University of Idaho.
Invasive Plant Atlas of the United States - Hoary Cress
University of Georgia. Center for Invasive Species and Ecosystem Health.
Invasive Species Compendium - Lepidium draba
CAB International.
TISI Inventory - Whitetop / Hoary Cress
Texas State University System. Texas Invasive Species Institute.
Weeds Australia - Hoary Cress (Lepidium draba)

Centre for Invasive Species Solutions; Atlas of Living Australia; Australian Government. Department of Agriculture, Water and the Environment.

Federal Government
Fire Effects Information System (FEIS) - Cardaria spp.
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
PLANTS Database - Whitetop
USDA. NRCS. National Plant Data Center.
U.S. National Plant Germplasm System - Lepidium draba

USDA. ARS. National Genetic Resources Program. GRIN-Global.

State and Local Government
Class C Noxious Weed: Hoary Cress
Washington State Noxious Weed Control Board.
Encycloweedia: Data Sheet - Lepidium genus
California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources
Hoary Cress Whitetop: Options for Control (PDF | 1.04 MB)
Lincoln County Noxious Weed Control Board (Washington).
See also: Weed I.D. and Options for Control for more species
Noxious Weed Species ID - Hoary Cress

Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.

Academic
Weed Control in Natural Areas in the Western United States: Hoary Cress (Whitetop), Lens-Podded and Hairy Whitetop (2013) (PDF | 252 KB)
University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets
Biology, Ecology, and Management of Whitetop (Cardaria spp.) (2011)
Montana State University Extension.
Professional
Noxious Weed Information - Hoary Cress (Whitetop)
Colorado Weed Management Association.
Weed Identification - Hoary Cress (Whitetop)
Montana Weed Control Association.

Citations

  • Integrated Taxonomic Information System. Lepidium draba. [Accessed Sep 10, 2014].
  • Zouhar, K. 2004. Cardaria spp. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.