Senecio hydrophilus
Water ragwort, alkali-marsh ragwort, Alkali-Marsh Ragwort
(c) crothfels, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Subshrub · Native
Senecio hydrophilus (Water ragwort) is a native California subshrub in the Asteraceae family, recognized by blue-green glaucous stems, wet alkaline habitat, and small or absent rays.
Water ragwort is a California native perennial found in northern Coast Ranges, Cascade Range, Sierra Nevada, Central Valley, Central Western California, and Great Basin in marshes, swampy places, and alkaline sites at elevations of 200 to 2,500 meters. Flowering from May to September, this plant produces yellow disk flowers in rounded clusters 20 to 40 heads wide, with distinctive black-tipped green phyllaries. Growing 4 to 10 meters tall with 1 to 4 blue-green, glaucous stems emerging from a short button-like caudex, it develops fleshy-fibrous roots. Its leaves are fleshy and variable, with proximal leaves 5 to 20 centimeters long, elliptic to oblanceolate, and becoming increasingly reduced and bract-like toward the stem tips. The fruit is small, glabrous, and approximately 2.5 to 3 millimeters long.
Identification and appearance
Key characters: 27 sympatric species; key features are blue-green glaucous stems, wet alkaline habitat, and small or absent rays
Habitat and range
Habitat: Marshes, swampy places, standing water, alkaline sites
Elevation: 200-2500 m
Outside California: to British Columbia, South Dakota, Colorado, Utah
Bloom period
Senecio hydrophilus blooms May-Sep.
How to tell it apart
vs Packera: Senecio has larger leaves (over 2.5 inches) and often black-tipped bracts; Packera has tiny leaves (under 1.5 inches) with green or reddish tips.; vs Sonchus: Senecio has yellow daisy flowers with a neat single row of bracts; Sonchus has dandelion-like flowers and milky sap when broken.; vs Dudleya: Senecio is in the sunflower family with daisy flowers; Dudleya is a succulent with thick fleshy leaves and star-shaped flowers.; vs Ericameria: Senecio has one main row of equal bracts around flower heads; Ericameria has 2-4 overlapping rows of unequal bracts.; vs Taraxacum: Senecio has branching stems with multiple flower heads; Taraxacum has leafless hollow stems with single dandelion-like heads.
Frequently asked questions
Is Senecio hydrophilus native to California?
Yes. Senecio hydrophilus is native to California (recorded as native).
When does Senecio hydrophilus bloom?
Senecio hydrophilus blooms May-Sep.
What plant family does Senecio hydrophilus belong to?
Senecio hydrophilus is in the Asteraceae family, genus Senecio.
What habitat does Senecio hydrophilus grow in?
Senecio hydrophilus grows in Marshes, swampy places, standing water, alkaline sites.
Related species
Other California species in the same genus, family, or bioregion.
- Senecio integerrimus — Lambstongue ragwort
- Senecio integerrimus var. exaltatus — Columbia ragwort
- Senecio integerrimus var. major — Lambs-tongue ragwort
- Senecio integerrimus var. ochroleucus — Pale-yellow ragwort
- Senecio linearifolius var. linearifolius — Linear-leaved australian fireweed
- Senecio lyonii — Island senecio
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.