Trifolium aureum
Large hop clover, Large Hop Clover
(c) Norma Malinowski, some rights reserved (CC BY), uploaded by Norma Malinowski · licence
Family: Fabaceae · Type: Herb · Not Native
Trifolium aureum (Large hop clover) is a non-native California herb in the Fabaceae family, recognized by bright yellow flowers turning brown diagnostic.
Large hop clover is a naturalized annual found in the San Joaquin Valley in disturbed areas at elevations especially below 200 meters. Flowering from July to August, this plant produces bright yellow flowers in compact heads 1 to 1.5 centimeters wide with flowers that quickly bend backward. Growing with ascending or erect stems, it reaches about 10 to 30 centimeters tall with a delicate, glabrous or slightly hairy structure. Its leaves have three leaflets, each 1 to 2.5 centimeters long, with oblanceolate or obovate shapes and lanceolate to ovate stipules. The flowers have a small calyx about 1.5 to 2 millimeters long, with a corolla that is striate and initially a vibrant yellow color.
Identification and appearance
Key characters: 26 sympatric species; bright yellow flowers turning brown diagnostic
Habitat and range
Habitat: Disturbed areas
Elevation: especially < 200 m
California counties: Tulare
Outside California: to British Columbia, northeastern United States, native to Europe
Bloom period
Trifolium aureum blooms Jul-Aug.
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 aureum native to California?
No. Trifolium aureum is not native to California (recorded as not native).
When does Trifolium aureum bloom?
Trifolium aureum blooms Jul-Aug.
Where in California does Trifolium aureum grow?
Trifolium aureum occurs in Tulare, at elevations of especially < 200 m.
What plant family does Trifolium aureum belong to?
Trifolium aureum is in the Fabaceae family, genus Trifolium.
What habitat does Trifolium aureum grow in?
Trifolium aureum grows in Disturbed areas.
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.