Flower Color: Yellow, pale-yellow; floral heads with ligulateflorets 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 species range map for Spiny Sowthistle, Sonchus asper:
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:
Arid West, FAC
Atlantic and Gulf Coastal Plain, FACU;
Eastern Mountains and Piedmont, FAC;
Great Plains, FAC;
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.
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 basalrosette 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.
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.