Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Sonchus asper, Spiny Sowthistle

Spiny Sowthistle has yellow or pale-yellow flowers on short bristly-glandular stalks and they look remarkably similar to the common Dandelion. Sonchus asper Spiny Sowthistle blooms from February to August or may bloom year-around with sufficient water. Sonchus asper Spiny Sowthistle is an herbaceous herb that emits milky sap. Plants are mostly hairless but have tiny glandular hairs. Sonchus asper Spiny Sowthistle has green or blue-green leaves that are soft, herbaceous; the leaves are simple and extremely variable with basal, mid and upper stem leaves. Sonchus asper Spiny Sowthistle upper leaves surround the stem (clasping) and are arranged alternately; the blades are spatulate to lanceolate; the margins wavy, often lobed and spiny. Sonchus asper Spiny Sowthistle grows to 5 feet (1.5 m) or more; 8 feet (2 m).  They may be found up to 8,000 feet (2,438 m) in elevations. Habitat preferences are slightly moist areas, roadsides, disturbed, ruderale and waste areas, cultivated areas and gardens. Sonchus asper

Scientific Name: Sonchus asper
Common Name: Spiny Sowthistle

Also Called: Perennial Sowthistle, Prickly Sow Thistle, Prickly Sow-thistle, Prickly Sowthistle, Rough Milk Thistle, Sharp-fringed-Sowthistle, Sow-thistle, Spiny Sow-thistle, Spiny-leaf Sow Thistle (Spanish: Chinita, Cerraja, Hoiidkam ‘i:waki)

Family: Asteraceae, Sunflower Family

Synonyms: (Sonchus nymanii)

Status: Introduced; Invasive

Duration: annual, biennial from a taproot.

Size: Up to 5 feet (1.5 m) or more; 8 feet (2 m)

Growth Form: Forb/herb; emits milky sap, plants hairless (glabrous) but with tiny glandular hairs; plants upright (erect); stems hollow.

Leaves: Green or blue-green (glaucous); soft, herbaceous; simple; extremely variable, basal, mid and upper stem leaves; lower leaves from a rosette, bases of upper leaves surround the stem (clasping), arranged alternately, blades spatulate to lanceolate; margins wavy, often lobed and spiny.

Flower Color: Yellow, pale-yellow; floral heads with ligulate florets that look remarkably similar to the common Dandelion flowers; flower heads on short bristly-glandular stalks (peduncle); fruit a cypsela with a white dandelion-like puff-ball seeds wind-borne dispersal.

Flowering Season: February to August or may bloom year-around

Elevation: Sea Level to 8,000 feet (2,438 m)

Habitat Preferences: slightly moist areas, roadsides, disturbed, ruderale and waste areas, cultivated areas and gardens.

Recorded Range: Throughout most of North America, northern Baja California and northern, central and southern Mexico.

North America & US County Distribution Map for Sonchus asper.

North America species range map for Spiny Sowthistle, Sonchus asper:

North America species range map for Spiny Sowthistle, Sonchus asper: Click image for full size map:
Click image for full size map

U.S. Weed Information: In North America Sonchus asper can be weedy or invasive according to the following authoritative sources:

  • Weeds of Kentucky and adjacent states: a field guide,
  • Weeds of Nebraska and the Great Plains,
  • Weeds of the United States and Canada,
  • Weeds of the West.

  • Plants included here may become weedy or invasive.

    U.S. Wetland Indicator: In North America Sonchus asper has the following wetland designations:
  • Alaska, FACU
  • Arid West, FAC
  • Atlantic and Gulf Coastal Plain, FACU;
  • Eastern Mountains and Piedmont, FAC;
  • Great Plains, FAC;
  • Midwest, FACU;
  • Northcentral & Northeast, FACU;
  • Western Mountains, Valleys, and Coast, FACU;

  • FAC = Facultative, occur in wetlands and non-wetlands
    FACU = Facultative Upland, usually occur in non-wetlands, but may occur in wetlands

    U.S. Threatened/Endangered Information: Unknown

    U.S. Invasive/Noxious Weed Information: Unknown

    Invasive/Noxious Weed Information: *CABI, and the *ISC* has identified Sonchus asper is listed as an “Invasive Species, Host Plant”.

    *CABI is The Centre for Agriculture and Bioscience International (CABI), Wallingford, Oxfordshire, England; he US Department of Agriculture is a lead partner with CABI.

    *ISC is The Invasive Species Compendium (ISC) is an encyclopedic resource that brings together a wide range of different types of science-based information to support decision-making in invasive species management worldwide.

    Genus Information: In North America there are 5 species and 8 accepted taxa overall for genus. Worldwide, The Plant List includes 131 accepted species names and a further 158 scientific names of infraspecific rank for the genus.

    The genus Sonchus was published in 1753 by Carl Linnaeus, (1707-1778)

    In the Southwestern United States: Arizona has 2 species of genus, California has 4 species, Nevada, New Mexico, Texas and Utah each have 3 species. Data approximate, subject to revision.

    Comments: An introduced and invasive European species, Spiny Asper has become naturalized throughout North America and Greenland. The basal rosette is similar to and may be confused with thistles which do not have milky sap. Other plants with similar appearances include; Annual Sowthistle, Sonchus oleraceus which has pointed lobes that clasp the stem and is generally much less prickly and Prickly Lettuce, Lactuca serriola which differs with spines on the midrib under the leaf.

    In Southwest Desert Flora also see Prickly Lettuce, Lactuca serriola.

    Importance to Wildlife, Birds and Livestock
    Although an introduced species, Sonchus asper has small but attractive flowers, the flowers and their seeds and plants may be visited by hummingbirds and/or small mammals including rodents and granivorous birds in search of nectar or food.

    Beneficial Value to Butterflies, Honey Bees and Insects
    Although an introduced species, Sonchus asper attractive flowers, the flowers and their plants may be visited by butterflies, moths, honeybees, native bees and other insects in search of food and nectar.

    The genus “Sonchus” (Son'chus:) the Greek name for Sowthistle.

    The genus Sonchus was published in 1753 by Carl Linnaeus, (1707-1778)

    The species epithet asper (Asperu'go:) derived from asper, “rough,” and used for a plant with rough or prickly leaves.

    Sonchus asper is used for a multitude of purposes by North American indigenous peoples.
  • Iroquois Drug, Pediatric Aid and Sedative; Compound infusion given to babies 'who cry until they hold their breath.'
  • Luiseno Food, Vegetable; Plant used for greens.
  • Mohave Food, Starvation Food; Young shoots roasted and eaten as a famine food.
  • Navajo, Kayenta Drug, Heart Medicine; Plant smoked or taken for palpitations.
  • Navajo, Kayenta Drug, Poison; Plant considered poisonous.
  • Pima Food, Unspecified; Stalks peeled and eaten raw like celery.
  • Pima Food, Unspecified; Tender leaves rubbed between the palms and eaten raw.
  • Pima Food, Vegetable; Tender leaves cooked as greens.
  • Pima, Gila River Food, Unspecified; Leaves eaten raw.

  • See complete listing of ethno-botanical uses at Native American Ethnobotany, University of Michigan, Dearborn.

    Date Profile Completed: 8/4/2012; updated 11/05/2020
    Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles
    U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed 11/04/2020.
    The Plant List (2013). Version 1.1. Published on the Internet;; accessed 11/05/2020.
    Philip E. Hyatt, FNA | Family List | FNA Vol. 19, 20 and 21 | Asteraceae; Sonchus, 2. Sonchus asper (Linnaeus) Hill, Herb. Brit. 1: 47. 1769.; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
    FNA 2006, Wiggins 1964, Kearney and Peebles 1969, Correll and Johnston 1970, Heil et al. 2013; Editors: S.Buckley 2010, F.S.Coburn 2015, A.Hazelton 2015, A.Hazelton 2017; from SEINet Field Guide, on-line; accessed 11/04/2020.
    CABI, 2020. Sonchus asper, (spiny sow-thistle). [Julissa Rojas-Sandoval, Department of Botany-Smithsonian NMNH, Smithsonian Institution, Washington DC, USA]. In: Invasive Species Compendium. Wallingford, UK: CAB International.
    David J. Keil & G. Ledyard Stebbins 2012, Sonchus oleraceus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on November 04, 2020.
    Wikipedia contributors, 'Sonchus asper', Wikipedia, The Free Encyclopedia, 9 October 2020, 02:26 UTC, [accessed 4 November 2020]
    Seiler, John, Peterson, John, North American species range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
    SEINet synonyms, scientific names, geographic locations, general information.
    Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 11/02/2020)
    IPNI (2020). International Plant Names Index. Published on the Internet, The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. [Retrieved 04 November 2020].