Cirsium pumilum aka Pasture Thistle

Cirsium pumilum goes by pasture thistle and fragrant thistle. It belongs to the daisy family, Asteraceae. Its native range spans southeastern Canada and the central and eastern United States. It grows in Ontario and North Carolina's Piedmont region. Wild plants occur in meadows, fields, roadsides, and disturbed ground. This short-lived herb grows for two or three years. It then flowers, sets seed, and dies.

Plants stand 1–3 feet (0.3–0.9 metres) tall with an upright form. They grow at a moderate rate and have a coarse texture. Young plants form a basal rosette of green leaves. Later leaves alternate along the stems and clasp them. These simple leaves have deep lobes and wavy edges. They reach 0.5–0.67 feet (0.15–0.20 metres) long, with some reaching 1 foot (0.3 metres). Dense white wool coats the leaf undersides. Short spines line the leaf edges. The stout green stems also bear woolly hairs and prickles.

Fragrant flower heads open in summer and fall. Their disc florets may be pink, purple, or white. Each dense, domed head holds 20–50 florets, without ray florets. Heads measure about 0.17–0.25 feet (0.05–0.08 metres) across. Small cream or tan achenes follow the flowers. Each carries a feathery pappus that helps wind spread it. The seed heads add interest in fall. Songbirds eat the oil-rich seeds and gather their tufts for nests.

Grow this thistle in full sun and well-drained soil. It prefers dry ground and tolerates drought. Clay and loam both suit it where drainage is good. It accepts acidic, neutral, and alkaline soils. The listed hardiness range covers USDA zones 3–8. Seed provides a way to raise new plants. Its short life means each plant dies after setting seed. Care needs are low, and deer tolerance adds value in gardens.

Pasture thistle suits meadow gardens and areas allowed to grow naturally. Bees and butterflies visit its flowers for nectar. Hummingbirds also visit the blooms. It hosts Painted Lady and Swamp Metalmark butterfly larvae. Native bees use its dead, hollow stems as nest sites. Retain 1–2 feet (0.3–0.6 metres) of dead stems for these bees. NC State reports no major pest or disease problems. It describes this native thistle as non-invasive and easier to control than some thistles. Its prickles remain a concern when handling plants.