Cirsium neomexicanum, New Mexico Thistle
Scientific Name: Cirsium neomexicanum
Common Name: New Mexico Thistle
Also Called: Desert Thistle, Foss Thistle, and Utah Thistle (Spanish: Cardo Santo)
Family: Asteraceae, Sunflower Family
Synonyms: (Carduus inamoenus, Carduus nevadensis, Cirsium arcuum, Cirsium humboldtense, Cirsium utahense)
Duration: Biennial or short lived perennial.
Size: 6 feet or more.
Growth Form: Forb/herb; erect, main stem, some branching above, spotted with cobweb like patches of short soft hairs; all parts with long stiff sharp spines.
Leaves: Green or greenish-gray; highly variable along stems; basal rosettes, upper oblong-elliptic to oblanceolate, deeply pinnatifid, uppermost leaves shorter, wing like bracts; spiny throughout.
Flower Color: Pink or purple, lavender or white; disk flowers only, large showy flower heads 2 or 3 inches wide, surrounded by sharp spine tipped bracts or phyllaries; solitary or 2 or 3 flower heads on tips of peduncles, loose corymb-like arrays.
Flowering Season: March to September, successful blooms following winter and spring rains and again after heavy summer monsoon rainfall.
Elevation: 1,000 to 6,500 feet.
Habitat Preferences: Plains, mesas, rocky hillsides, foothills, roadsides and washes.
Recorded Range: In the United States in AZ, CA, CO, NM, NV and UT and in northwest Mexico. New Mexico Thistle is scattered throughout most of Arizona.
U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available
Comments: New Mexico Thistle is not an aggressive noxious weed however the genus Cirsium is often included in many weed lists presumably through its relationship to aggressive thistles such as the European invasive Bull Thistle, Cirsium vulgare. It attracts many different insects including bees, wasps and butterflies. A southwestern species, the geographic range of New Mexico Thistle suggests it to be a Mojave Desert species although it is native to and common in both the Mojave and Sonoran Deserts.
Navajo Indians used parts of the plant to reduce chills and fevers and a cold infusion of root was used as a wash for eye diseases. See species account from Native American Ethnobotany, University of Michigan, Dearborn.