Cirsium hydrophilum

Suisun thistle

Family: Asteraceae · Type: perennial · Native

Suisun thistle is a rare California native perennial found in marsh and wetland habitats at low elevations. Flowering from June to September, this plant produces pale rose-purple flowers in heads 1.5 to 2.5 centimeters wide, with delicate clusters emerging from cobwebby stems. Growing up to 2.2 meters tall with an upright habit, the thistle develops a complex branching structure that becomes increasingly glabrous with age. Its leaves are distinctive, with lower leaves spanning 3 to 9 decimeters and featuring deeply lobed edges marked by spiny margins, while upper leaves become progressively smaller and more clasping. The plant's phyllaries are graduated and minutely spiny-fringed, with spreading tip-spines adding to its intricate architectural form.

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