Parthenium hysterophorus

Santa maria

Family: Asteraceae · Type: perennial

Conservation status: Cal-IPC Yes

Santa maria is a naturalized perennial found in disturbed ground and dry creek channels at elevations below 50 meters. Flowering from March to November, this plant produces small white ray flowers in panicle-like clusters with heads 4 to 5 millimeters in diameter. Growing with much-branched stems 30 to 200 centimeters tall that are ribbed and minutely hairy, it develops a complex branching structure. Its leaves are distinctive, with proximal leaves being petioled and gland-dotted, while distal leaves become progressively less divided, ending in linear terminal segments. The plant produces distinctive fruits with black, three-angled ray fruits bearing two small white scales.

Habitat: Disturbed ground, dry creek channels

Bloom period: Mar-Nov

Elevation: < 50 m

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