Cirsium douglasii

Swamp thistle, Swamp Thistle

Family: Asteraceae · Type: perennial · Native

Swamp thistle is a California native perennial herb found in wet meadows and riparian areas across the state's coastal and central regions. Flowering from June to September, this plant produces dark rose-purple (occasionally white) flowers in clustered heads 2 to 4.5 centimeters wide, with distinctive involucres featuring phyllaries tipped with dark purple patches and spreading spines. Growing 60 to 250 centimeters tall with multiple much-branched stems covered in gray, felt-like hairs, it develops a robust taproot or woody base. Its leaves are particularly notable, with basal leaves 30 to 110 centimeters long, featuring coarsely toothed or deeply lobed blades and spiny-toothed petioles, while cauline leaves have ear-like expanded bases with spiny wings. The plant's fruit is small, approximately 5 to 6 millimeters long, accompanied by a pappus 15 to 20 millimeters in length.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.