Purple Thistle

Cirsium horridulum

SIR-see-um hor-id-YOO-lum          

Asteraceae

Native to: Maine and Pennsylvania, south into Florida and west to Texas.

Also found in the West Indies, Mexico and Central America.

Florida abundance and distribution: This plant may be considered a protected species.  This is a frequent native weed of pinelands and prairies.  It is often found along the edges of salt marshes and is typical in overgrazed pastures.  Grown in full sun exposure, drought-tolerant when establish, low salt water tolerance.   Propagation method is seeds.  Soils from moist, well-drained to moderately well-drained sandy or limestone soils, without humus.

Recognition:    Biennial with a branching stem 1’-5’ tall, with alternate leaf arrangement. The leaves are very spiny and between 6 to 10 inches long, lanceolate, pinnately lobed, stalkless and clasping the stem, with spiny margins and tips.  The basal rosette is broader than tall.  Flowers in large variably colored heads (2-3 inches diameter) including pale pink, rose/mauve, pale yellow, purple, cream/tan.  It blooms all year long; peak spring-fall.  The flower heads are surrounded by erect, narrow, spiny bract-like leaves.  Unlike other local thistles, these bracts nestling the flower head are pinnately lobed and spine-tipped. 

Others:     Also known as Yellow Thistle, Bull Thistle, Spiny Thistle.  The name “horridulum" refers to the very prickly leaves; it must be handle with caution. This is a major attractor of insect pollinators (butterflies bees, wasps and/or birds).  This plant is a larval host plant and a nectar plant. The flowering heads are often torn apart by beetles.

Contributed by: Grace Walton