Purple Thistle (Non-Grass)
Cirsium species (Likely Cirsium horridulum) · Biennial or Perennial Herbaceous Dicot
Grass Family
Asteraceae (Sunflower Family) - Not a member of Poaceae
Grass Category
Invasive/Weed Grass (Often found in lawns and pastures)
Variety / Cultivar
Wild specimen; sometimes referred to as 'Purple Thistle' or 'Yellow Thistle'
Hardiness Zones
USDA Zones 5-10; extremely heat tolerant and goes dormant or remains as a flat rosette in winter.
About This Grass
A spiny, herbaceous plant forming a low-growing basal rosette. Features deeply lobed, lance-shaped leaves with sharp spines along the margins. The center often exhibits vibrant purple or reddish pigmentation.
Blade Characteristics
Leaves (not blades) are deeply pinnatifid, 10-20cm long, featuring sharp yellowish spines, a prominent purple midrib, and a leathery texture with no ligule or auricles.
Root System
Deep, fleshy taproot that provides significant drought resistance and makes manual removal difficult; lacks stolons or rhizomes.
Growing Information
Origin Region
Native to North America (Eastern and Southern US)
Growth Habit
Rosette-forming (Basal clump) with a deep taproot
Sunlight & Water Needs
Full sun; highly drought-tolerant; prefers well-drained sandy or loamy soils with pH 5.5 to 7.0.
Mowing & Maintenance
Not applicable for turf. In lawns, frequent low mowing can prevent seed production, but the rosette stays below mower blades. Thrives in low-maintenance areas.
Special Characteristics
Highly resistant to herbivory due to sharp spines; excellent salt tolerance; primary 'special' trait is being a difficult-to-kill lawn weed.
Ecological Information
Native to the US; provides high-value nectar for pollinators (bees, butterflies) and seeds for goldfinches; considered a noxious weed in managed turf and agriculture.