Sonchus arvensis - L.
Field Sowthistle
Other English Common Names: Perennial Sow-thistle
Other Common Names: field sowthistle
Taxonomic Status: Accepted
Related ITIS Name(s): Sonchus arvensis L. (TSN 38421)
French Common Names: laiteron des champs
Unique Identifier: ELEMENT_GLOBAL.2.148668
Element Code: PDAST8R010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Aster Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Asterales Asteraceae Sonchus
Check this box to expand all report sections:
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: Sonchus arvensis
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 (22Jun2016)

U.S. & Canada State/Province Status
United States Alaska (SNA), California (SNA), Colorado (SNA), Connecticut (SNA), Delaware (SNA), District of Columbia (SNA), Idaho (SNA), Illinois (SNA), Indiana (SNA), Iowa (SNA), Kansas (SNA), Kentucky (SNA), Louisiana (SNA), Maine (SNA), Maryland (SNA), Massachusetts (SNR), Michigan (SNA), Minnesota (SNA), Mississippi (SNA), Missouri (SNA), Montana (SNA), Nebraska (SNA), Nevada (SNA), New Hampshire (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), North Carolina (SNA), North Dakota (SNA), Ohio (SNA), Oregon (SNA), Pennsylvania (SNA), Rhode Island (SNA), South Dakota (SNA), Tennessee (SNA), Utah (SNA), Vermont (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada Alberta (SNA), British Columbia (SNR), Manitoba (SNA), New Brunswick (SNA), Newfoundland Island (SNA), Northwest Territories (SNA), Nova Scotia (SNA), Nunavut (SNA), Ontario (SNA), Prince Edward Island (SNA), Quebec (SNA), Saskatchewan (SNA), Yukon Territory (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces
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 AKexotic, CAexotic, COexotic, CTexotic, DCexotic, DEexotic, IAexotic, IDexotic, ILexotic, INexotic, KSexotic, KYexotic, LAexotic, MA, MDexotic, MEexotic, MIexotic, MNexotic, MOexotic, MSexotic, MTexotic, NCexotic, NDexotic, NEexotic, NHexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, ORexotic, PAexotic, RIexotic, SDexotic, TNexotic, UTexotic, VAexotic, VTexotic, WAexotic, WIexotic, WVexotic, WYexotic
Canada ABexotic, BC, MBexotic, NBexotic, NFexotic, NSexotic, NTexotic, NUexotic, ONexotic, PEexotic, QCexotic, SKexotic, YTexotic

Range Map
No map available.

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: Medium/Low
Rounded I-Rank: Medium
I-Rank Reasons Summary: This is primarily known as a problematic weed species of annual croplands, especially in the northern U.S. It is typically found in cultivated fields, roadside ditches, and other very ruderal habitats, and in most parts of the U.S. it is not a major problem in natural areas. However, it has extremely wide environmental tolerances and in a few situations at least it has invaded natural communities of high conservation concern. Additional research on this species' impact in natural areas, particularly in naturally disturbed wet and/or saline habitats in parts of the West, is warranted. It can be an aggressive invader of disturbed areas and, once established, can persist for long periods and is difficult to control or eradicate. It may have the potential to become more abundant in the southern continental U.S. and to establish in Hawaii.
Subrank I - Ecological Impact: Low/Insignificant
Subrank II - Current Distribution/Abundance: High
Subrank III - Trend in Distribution/Abundance: Medium/Low
Subrank IV - Management Difficulty: High/Low
I-Rank Review Date: 18Apr2006
Evaluator: K. Maybury
Native anywhere in the U.S?
Native Range: Europe

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
Comments: This species has been listed among the most frequently listed in a recently compiled database of noxious weeds in the United States and Canada (Skinner et al., 2000).

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

Subrank I - Ecological Impact: Low/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance/Insignificant
Comments: No significant impacts reported.

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: This coarse perennial herb can reach 2 m in height (Butterfield et al. 1996) and can form vigorous stands; it could potentially alter the density and height of the herbaceous layer.

3. Impact on Ecological Community Composition:Medium/Low significance
Comments: McWilliams (2004), who conducted an extensive literature review, notes that information about the impacts of this species on natural communities is absent from the literature; however, Butterfield et al. (1996) state that, once established, this species has the potential to modify existing native plant communities and it may modify or delay succession through the suppression or reduction of plant species that might otherwise establish over time.

4. Impact on Individual Native Plant or Animal Species:Insignificant
Comments: No indications of disproportionate impacts.

5. Conservation Significance of the Communities and Native Species Threatened:Medium/Low significance
Comments: This is primarily known as a problem weed in cultivated fields and is also found in other highly disturbed areas and waste places such as roadside ditches (Butterfield et al. 1996, Rutledge and McLendon 1996, McWilliams 2004). However, it can also invade riparian systems (e.g., Rice and Harden 2002), saline meadows and prairies (McWilliams 2004), and other habitats that may be of much greater conservation concern. It has been found (but was not frequent or abundant) in the habitat of the Federally Listed Threatened desert tortoise in the Mojave and Colorado deserts (Brooks and Esque 2002). McWilliams (2004) notes that it can invade open wet sites even with little soil disturbance and further notes that information about the impacts of this species on natural communities is absent from the literature. Per a 2006 email discussion among botanists and ecologists in the Network of Natural Heritage programs and Conservation Data Centres in the U.S. and Canada, this species is strictly ruderal and not thought to be a problem in any high quality natural areas in much of the U.S.: Maine, New York, West Virginia, Kentucky, Ohio, Michigan Wisconsin, Missouri, and Nevada and other adjacent Great Basin areas (pers. comms. from D. Cameron, S. Young, J. Vanderhorst, D. White, R. Gardner, M. Penskar, K. Kearns, T. Smith, and J. Morefield); it is probably not a serious problem in Colorado (J. Rocchio and K. Schultz, pers. comms.) although it has established in some native riparian communities there (J. Rocchio, pers. comm.). However, there appear to be special circumstances where the species does (or could) impact high quality habitats and native species of conservation concern. Most notable are high-salinity streamside habitats in Wyoming and Idaho where it occurs with great abundance with Spiranthes diluvialis, a Listed Threatened species (G. Jones, pers. comm; B. Colket, pers. comm.; Jones 2000; Jones 2001). The disturbance that allows Sonchus arvensis to establish in these areas is natural flooding, rather than livestock or human activities (G. Jones, pers. comm.). Other areas where there may be reason for concern are native habitats in the ecotone between wetland and upland in South Dakota, where it can be a pernicious invader (although not as abundant as Cirsium arvense) (D. Ode, pers. comm.) and some coastal salt marshes (it has been noted in eastern Canada in very remote and otherwise pristine salt marsh areas per W. Bakowsky and S. Blaney, pers. comms.). More research on this question is clearly warranted.

Subrank II. Current Distribution and Abundance: High

6. Current Range Size in Nation:High significance
Comments: Documented in most of the U.S. though less frequent in the South (J. Kartesz, unpublished draft distribution data).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Moderate significance
Comments: This species has been listed among the most frequently listed in a recently compiled database of noxious weeds in the United States and Canada (Skinner et al., 2000). Negative impacts assumed only in portions of the generalized range. This species is very rare to infrequent in the southern states and is not impacting natural areas in many areas.

8. Proportion of Nation's Biogeographic Units Invaded:High significance

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High significance
Comments: Found in a wide range of habitats including very wet soils, dry soils, and saline situations (McWilliams 2004) ranging from Maine and Alaska to the Mojave Desert.

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

10. Current Trend in Total Range within Nation:Medium/Low significance
Comments: Unknown but assumed not expanding in all directions nor decreasing.

11. Proportion of Potential Range Currently Occupied:Low significance
Comments: Already widespread but there is no obvious reason why this species could not spread farther into the Southeast and into Hawaii (where it has not yet been reported). It is clearly tolerant of subtropical and tropical conditions as it occurs in Fiji, Samoa, Tonga, and New Caledonia (PIER 2003) as well as Louisiana and possibly Mississippi (J. Kartesz, unpublished draft distribution data).

12. Long-distance Dispersal Potential within Nation:Moderate significance
Comments: Seeds are primarily wind dispersed (Butterfield et al. 1996, Harris and Peschken 2005) but maximum wind dispersal distance may be only about 33 feet (Sheldon and Burrows 1973 as cited in McWilliams 2004). The seeds are also spread through contaminated hay and via animal fur (Harris and Peschkin 2005) and presumably through contaminated agricultural seed since the first introduction to the U.S. was thought to be via contaminated seed (Long 1922 as cited in McWilliams 2004).

13. Local Range Expansion or Change in Abundance:Unknown
Comments: Unknown.

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Low significance
Comments: This is an early successional species (McWilliams 2004) that is somewhat shade tolerant but grows best in full sun (Butterfield et al. 1996). It is essentially a pioneer species but it can persist at mid-successional sites (those disturbed in the last 11-50 years) and may even delay succession (Butterfield et al. 1996). The degree to which it can persist once established is of concern (B. Bennett, pers. comm., W. Rapp, pers. comm.); it has persisted around an old homestead on an infrequently visited island in southeastern Alaska for approximately 70 years with minimal human disturbance (W. Rapp, pers. comm.).

15. Similar Habitats Invaded Elsewhere:Medium/Low significance
Comments: Escaped and naturalized in similar habitats in the Pacific Islands (PIER 2003) and yet not currently documented for the U.S. tropics (Hawaii and South Florida). Also escaped in Canada.

16. Reproductive Characteristics:High significance
Comments: Characterized as a "rapid and opportunistic invader" by Harris and Peschken (2005). This species is a prolific seed producer (McWilliams 2004) with seeds that remain viable for at least 3 years (McWilliams 2004) or as long as 6 (Rutledge and McLendon 1996). It reproduces both vegetatively and by seed and even tiny fragments of the easily-broken roots can establish new plants (Harris 1996 as cited in McWilliams 2005). The spreading rootstocks can reach a depth of 2 m (Butterfield et al. 1996), which enables the plants to survive even deep cultivation and fire.

Subrank IV. General Management Difficulty: High/Low

17. General Management Difficulty:High/Moderate significance
Comments: McWilliams (2004) notes that there is no information on control of this species in natural areas but sources (focused on control in annual croplands) indicate that the species is resistant to most broadleaf herbicides. The deep roots make tilling and fire poor alternatives, so control is assumed to be difficult.

18. Minimum Time Commitment:Low significance
Comments: Rutledge and McLendon (1996) state that continuous removal of of above ground parts over a period of 80 days will exhaust underground food reserves.

19. Impacts of Management on Native Species:High/Low significance
Comments: Uncertain. Continuous removal (cutting or mowing), assuming it is possible at all, would would presumably be extremely difficult to do in a selective way.

20. Accessibility of Invaded Areas:Low significance
Comments: Many infestations are on agricultural and other private lands but this is considered a noxious weed and presumably there would be no objections to control efforts that would benefit nearby natural areas by eliminating the seed source for reinvasion following disturbance.

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).

  • Brooks, M. L. and T. C. Esque, 2002. Alien plants and fire in desert tortoise (Gopherus agassizii) habitat of the Mojave and Colorado deserts. Chelonian Conservation Biology 4(2): 330-340.

  • Butterfield, C., J. Stubbendieck, and J. Stumpf. 1996. Species abstracts of highly disruptive exotic plants. Jamestown, ND: Northern Prairie Wildlife Research Center. Online: (Accessed 2006.)

  • Harris, P. and D. P. Peschken. 2005. Classical biological control of weeds: Biology of target weeds: Perennial sow-thistle, Sonchus arvensis L. Agriculture and Agri-Food Canada, Lethbridge Research Centre. Online: Last modified 2005-08-03. Accessed 2006.

  • Jones, G.P. 2000. 1999 Survey of BLM-managed public lands in southwestern Wyoming for Ute ladies tresses (Spiranthes diluvialis) and for designated weeds. Report prepared for the BLM Rock Springs Field Office by the Wyoming Natural Diversity Database (University of Wyoming).

  • Jones, G.P. 2001. 2000 Survey of BLM-managed public lands in southwestern Wyoming for Ute ladies tresses (SPIRANTHES DILUVIALIS) and for designated weeds. Report prepared for the BLM Rock Springs Field Office by the Wyoming Natural Diversity Database (University of Wyoming).

  • 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. 1996. Species distribution data at state and province level for vascular plant taxa of the United States, Canada, and Greenland (accepted records), from unpublished data files at the North Carolina Botanical Garden, December, 1996.

  • McWilliams, J. 2004. Sonchus arvensis. In: Fire Effects Information System. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Online: Accessed 2006.

  • Pacific Island Ecosystems at Risk (PIER). 2003. Sonchus arvensis. United States Department of Agriculture Forest Service Institute of Pacific Island Forestry. Last updated 22 November 2003. Online: (Accessed 2006.)

  • Rice, P. M. and J. Hardin. 2002. Riparian plant community structure at Grant-Kohrs Ranch. University of Montana, Missoula.

  • Rutledge, C.R., and T.McLendon. 1996. An assessment of exotic plant species of Rocky Mountain National Park. Department of Rangeland Ecosystem Science, Colorado State University. Jamestown, ND: Northern Prairie Wildlife Research Center Online: (Accessed 2006.)

  • Skinner, K., L. Smith, and P. Rice. 2000. Using noxious weed lists to prioritize targets for developing weed management strategies. Weed Science, 48: 640-644.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at were updated to be current with NatureServe's central databases as of November 2016.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2017 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.