Lepidium latifolium - L.
Broadleaf Pepper-grass
Other English Common Names: Broadleaf Pepperweed
Other Common Names: broadleaved pepperweed
Taxonomic Status: Accepted
Related ITIS Name(s): Lepidium latifolium L. (TSN 503379)
Unique Identifier: ELEMENT_GLOBAL.2.149719
Element Code: PDBRA1M0J0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Mustard Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Capparales Brassicaceae Lepidium
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Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Lepidium latifolium
Conservation Status

NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (13Oct2016)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arizona (SNA), California (SNA), Colorado (SNA), Connecticut (SNA), Idaho (SNA), Illinois (SNA), Indiana (SNA), Kansas (SNA), Massachusetts (SNR), Missouri (SNA), Montana (SNA), Nebraska (SNA), Nevada (SNA), New Mexico (SNA), New York (SNA), Oregon (SNA), Texas (SNA), Utah (SNA), Washington (SNA), Wyoming (SNA)
Canada Alberta (SNA), British Columbia (SNA), Manitoba (SNA), Ontario (SNA), Quebec (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States AZexotic, CAexotic, COexotic, CTexotic, IDexotic, ILexotic, INexotic, KSexotic, MA, MOexotic, MTexotic, NEexotic, NMexotic, NVexotic, NYexotic, ORexotic, TXexotic, UTexotic, WAexotic, WYexotic
Canada ABexotic, BCexotic, MBexotic, ONexotic, QCexotic

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
NV Carson City (32510), Churchill (32001), Douglas (32005), Elko (32007), Eureka (32011), Humboldt (32013), Lander (32015), Lincoln (32017), Lyon (32019), Nye (32023), Pershing (32027), Storey (32029), Washoe (32031), White Pine (32033)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
15 Lower Virgin (15010010)+, White (15010011)+, Muddy (15010012)+, Meadow Valley Wash (15010013)+
16 Southern Great Salt Lake Desert (16020306)+, Upper Humboldt (16040101)+, North Fork Humboldt (16040102)+, South Fork Humboldt (16040103)+, Pine (16040104)+, Middle Humboldt (16040105)+, Reese (16040107)+, Lower Humboldt (16040108)+, Little Humboldt (16040109)+, Upper Quinn (16040201)+, Lower Quinn (16040202)+, Massacre Lake (16040204)+, Lake Tahoe (16050101)+, Truckee (16050102)+, Pyramid-Winnemucca Lakes (16050103)+, Granite Springs Valley (16050104)+, Upper Carson (16050201)+, Middle Carson (16050202)+, Carson Desert (16050203)+, East Walker (16050301)+, West Walker (16050302)+, Walker (16050303)+, Dixie Valley (16060001)+, Northern Big Smoky Valley (16060004)+, Diamond-Monitor Valleys (16060005)+, Long-Ruby Valleys (16060007)+, Spring-Steptoe Valleys (16060008)+, Dry Lake Valley (16060009)+, Hot Creek-Railroad Valleys (16060012)+
18 Honey-Eagle Lakes (18080003)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History Not yet assessed
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank)
Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: High
Rounded I-Rank: High
I-Rank Reasons Summary: Capable of invading natural ecosystems in riparian areas, marshes, estuaries, and other wetlands where encroaching on several rare plant populations and threatening several animals, including an endangered mouse. Tolerates high salinity and can salinify soils; excludes or inhibits regeneration of native plants. Currently widespread in the Western U.S. and with recent, rapid increases in range and abundance.
Subrank I - Ecological Impact: High
Subrank II - Current Distribution/Abundance: Medium
Subrank III - Trend in Distribution/Abundance: High/Medium
Subrank IV - Management Difficulty: High/Medium
I-Rank Review Date: 31Dec2003
Evaluator: Maybury, K.
Native anywhere in the U.S?
Native Range: Europe to southwestern Asia (Himalayan region)

Download "An Invasive Species Assessment Protocol: Evaluating Non-Native Plants for their Impact on Biodiversity". (PDF, 1.03MB)
Provide feedback on the information presented in this assessment

Screening Questions

S-1. Established outside cultivation as a non-native? YES

S-2. Present in conservation areas or other native species habitat? Yes

Subrank I - Ecological Impact: High

1. Impact on Ecosystem Processes and System-wide Parameters:Moderate significance
Comments: Lepidium latifolium can increase soil salinity by taking salt from deep in the soil profile and transporting it upwards, concentrating it near the surface (Blank and Young 1997 as cited in Renz 2000).

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: Forms dense stands; possibly more dense than the native herbaceous layer in many cases, especially in high salt areas. Can inhibit the regeneration of woody species such as willows, cottonwoods in riparian areas.

3. Impact on Ecological Community Composition:High significance
Comments: Numerous sources from different areas of the western U.S. note that this speices forms dense, monospecific stands that displace/exclude native species.

4. Impact on Individual Native Plant or Animal Species:High significance
Comments: Interferes with the regeneration of willows and cottonwoods, reducing food and cover for bird species in riparian areas ( Krueger and Sheley 1999, Morisawa 1999). The species' semi-woody stems inhibit nesting of waterfowl (Trumbo 1994 as cited in Renz 2000) and it outcompetes the native grasses that provide food for native waterfowl (Howald, not dated). Outcompetes many native plant species. Dense litter layers form under big infestations, inhibiting the emergence of annual plants (Renz 2000).

5. Conservation Significance of the Communities and Native Species Threatened:High significance
Comments: In addition to hay meadows, irrigated pastures, roadsides, irrigation ditches, etc., this plant invades natural ecosystems in riparian areas/floodplains, marshes, estuaries, and other wetlands. It is encroaching on several rare plant populations in California, including Cordylanthus mollis ssp. mollis, Cirsium hydrophilum ver. hydrophilum, and Aster lentus (Skinner and Pavlik 1994). Poses a threat to the endangered salt marsh harvest mouse , the California black rail, and California clapper rail (Howald, not dated).

Subrank II. Current Distribution and Abundance: Medium

6. Current Range Size in Nation:High significance
Comments: All western states except Alaska. Also infesting some of the Midwest and New England (Kartesz 1999).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Low significance
Comments: Somewhat restricted to wetlands (but occurs in uplands), but many types of wetland areas impacted.

8. Proportion of Nation's Biogeographic Units Invaded:High significance
Comments: Occurs from high elevation coniferous forests to saline deltas in the Intermountain West (Lantz and Simon, not dated). Found from coastal areas to intermountain and mountain habitats; found in nearly all counties in California (Renz 2000).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High significance
Comments: Wide elevational range; wide salinity range; tolerates, but does not require, salty soils; tolerates highly alkaline soils. Found in coastal marshes and estuaries (Pacific and New England coasts), desert flooplains, mountain streamsides and other riparian areas, inland wetlands of all types.

Subrank III. Trend in Distribution and Abundance: High/Medium

10. Current Trend in Total Range within Nation:High/Moderate significance
Comments: Unclear, but apparently the spread to the desert southwest and Texas was recent, or at least recently reported.

11. Proportion of Potential Range Currently Occupied:Medium/Low significance
Comments: There seems to be no climatic reason why this plant could not invade the Mid-Atlantic and southeastern U.S.

12. Long-distance Dispersal Potential within Nation:Moderate significance
Comments: Apparently, mostly spreads by root fragments carried by currents/floodwaters. Has also been introduced to new areas via imported soil and hay bales containing roots or seeds.

13. Local Range Expansion or Change in Abundance:High significance
Comments: Renz (2000) indicates recent, rapid increases in populations in the West. According to Howald (not dated but recent), within the last fifteen years populations in California have expanded and the plant has significantly increased its overall range. Krueger and Sheley (1999) note that this plant is "quickly spreading across the West."

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:High/Moderate significance
Comments: Does not appear require major disturbance to become established.

15. Similar Habitats Invaded Elsewhere:Medium/Low significance
Comments: Has invaded Australia (Renz 2000) but specific habitats unknown; possibly similar to those already invaded in California.

16. Reproductive Characteristics:High/Moderate significance
Comments: Roots fragment easily and fragments become established elsewhere. Extensive root system that resprouts. Prolific seed production (although seed viability is believed to be short and germination under field conditions is low according to Renz (2000)).

Subrank IV. General Management Difficulty: High/Medium

17. General Management Difficulty:High significance
Comments: Extensive, very deep root system with roots that can remain dormant for several years (Renz 200) and waxy leaves (Lantz and Simon, not dated) make this species very difficult to control. Herbicides have been effective, but some of the most effective should not be used close to open water. Major infestations may also require litter removal for native plants to recover (Renz 2000).

18. Minimum Time Commitment:Medium/Low significance
Comments: Monitoring of resprouting would need to be done over several years.

19. Impacts of Management on Native Species:Medium/Low significance

20. Accessibility of Invaded Areas:Unknown

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Blank, R. and J. A. Young. 1997. Lepidium latifolium: Influences on soil properties, rates of spread, and competitive stature. Pages 69-80 in J. H. Brock, M. Wade, P. Pysek, and D. Green, eds. Plant Invasions: Studies from North America and Europe. Backhuys, Leiden.

  • Bossard, C.C., J.M. Randall, and M. Hoshovsky. (eds.) 2000. Invasive Plants of California's Wildlands. University of California Press, Berkeley, CA.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • Krueger, J. and R. Sheley. 1999. Perennial pepperweed (Lepidium latifolium). Montguide 9906, May 1999. Montana State University Extension Service. Available: http://www.montana.edu/wwwpb/pubs/mt9906.pdf. (Accessed 2003).

  • Lantz, L. and B. Simon. Not dated. Perennial pepperweed technical bulletin. http://www.nwcb.wa.gov/weed_info/pepperweed.html. (Accessed 2003).

  • Morisawa, T. 1999. Weed notes: Lepidium latifolium. The Nature Conservancy, Arlington, VA. Available: http://tncweeds.ucdavis.edu/moredocs/leplat01.html.

  • Renz. M. J. 2000. Element Stewardship Abstract for Lepidium latifolium. The Nature Conservancy, Arlington, VA. Available: http://tncweeds.ucdavis.edu/esadocs/documnts/lepilat.html.

  • Trumbo, J. 1994. Perennial pepperweed: A threat to wildland areas. CalEPPC Newsletter 2:4-5.

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