Trifolium hirtum
Rose clover
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Family: Fabaceae · Type: Herb · Not Native
Conservation status: Cal-IPC Yes
Trifolium hirtum (Rose clover) is a non-native California herb in the Fabaceae family, recognized by densely plumose calyx lobes create distinctive bristly heads.
Rose clover is a naturalized annual found in California's Central and South Coast, North Coast, and South Coast Ranges in disturbed areas and roadsides at elevations below 2,060 meters. Flowering from April to May, this plant produces pink flowers in dense, bristly heads approximately 1.5 to 2 centimeters wide. Growing with ascending or erect hairy stems, the plant develops leafy branches with distinctive bristle-tipped stipules. Its leaves have three obovate leaflets 1 to 2.5 centimeters long, with each leaflet broadly egg-shaped and rounded at the tip. The flower's calyx is notable for its plumose, bristle-like lobes that extend well beyond the tube, giving the plant a characteristic fuzzy appearance.
Identification and appearance
Key characters: 68 sympatric species; densely plumose calyx lobes create distinctive bristly heads
Habitat and range
Habitat: Disturbed areas, roadsides
Elevation: < 2060 m
California counties: Amador, Los Angeles, Riverside, San Luis Obispo, Orange, San Diego, Kern, Mariposa, Ventura, Fresno, Monterey, Solano, Sacramento, Tulare, Butte, Placer, San Bernardino, Santa Barbara, Yuba, Lake, Calaveras, Marin, Madera, San Francisco, El Dorado, Yolo, San Mateo, Contra Costa, Alameda, Shasta, Mendocino, Santa Clara, San Joaquin, Glenn, Nevada, Colusa, Sonoma, Siskiyou, Santa Cruz, Sutter, Tuolumne, Napa, Trinity, Tehama, Sierra, Stanislaus, Humboldt
Outside California: sporadic to eastern United States, native to Eurasia, northern Africa
Bloom period
Trifolium hirtum blooms Apr-May.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Medicago: Trifolium flowers persist around fruits; Medicago flowers fall off leaving exposed coiled fruits.; vs Oxalis: Trifolium has pea-shaped flowers; wood-sorrels (Oxalis) have 5-petaled star-shaped flowers and heart-notched leaflets.; vs Melilotus: Trifolium flowers persist enclosing fruits; Melilotus flowers fall off leaving exposed ridged pods.; vs Castilleja: Trifolium has pea flowers and 3 toothed leaflets; paintbrush (Castilleja) has tubular flowers in colorful bracts.; vs Acmispon: Trifolium leaflets have toothed edges; Acmispon leaflets have smooth untoothed margins.
Frequently asked questions
Is Trifolium hirtum native to California?
No. Trifolium hirtum is not native to California (recorded as not native).
When does Trifolium hirtum bloom?
Trifolium hirtum blooms Apr-May.
Where in California does Trifolium hirtum grow?
Trifolium hirtum occurs in Amador, Los Angeles, Riverside, San Luis Obispo, Orange, San Diego, Kern, Mariposa and other counties, at elevations of < 2060 m.
What plant family does Trifolium hirtum belong to?
Trifolium hirtum is in the Fabaceae family, genus Trifolium.
Is Trifolium hirtum invasive in California?
Trifolium hirtum is listed by Cal-IPC with an invasiveness rating of Yes.
Related species
Other California species in the same genus, family, or bioregion.
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.