Page authors: Don Knoke, David Giblin
Trifolium dubium
least hop clover, suckling clover

Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across much of North America to the Atlantic Coast.

Habitat: Forest openings, roadsides, fields, lawns, wastelots, and other disturbed sites.

Flowers: April-September

Origin: Introduced from Europe

Growth Duration: Annual

Conservation Status: Not of concern


Sparsely pubescent annual, the stems 1-several, 1-5 dm. long, prostrate or ascending to erect.


Leaves trifoliate, short-petiolate; leaflets obovate to obcordate, 5-20 mm. long, denticulate above mid-length; stipules 3-5 mm. long, acuminate, entire.


Inflorescence of 3- to 20-flowered heads, 6-7 mm. broad, on short, axillary peduncles; flowers pea-like, yellow, reflexed, 3-3.5 mm. long; calyx glabrous, 5-nerved, half as long as the corolla, the 5 teeth narrowly lanceolate, entire, the upper 2 broader than and half as long as the lower 3; banner hood-like, folded, nearly hiding the shorter wings and keel.


Pod 1-seeded, longer than the attached style.

Accepted Name:
Trifolium dubium Sibth.
Publication: Fl. Oxon. 231. 1794.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Trifolium dubium in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Trifolium dubium checklist entry.

E-Flora BC: Trifolium dubium atlas page.

CalPhotos: Trifolium dubium photos.

USDA Plants: Trifolium dubium information.

11 photographs:
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