Crop and Soil Environmental News, September 2004

Do you know the hop clovers???

Large hop clover (Trifolium campestre Schreb.,)
Other common name:: low hop clover

Small hop clover (Trifolium dubium Sibth.,)
Other common name: least hop clover

Seed:

• oval, yellow and red colored
• 1/3 size of alfalfa, like miniature crimson clover
• very glossy

Large hop clover field

Peduncles often exceeding the subtending leaves.

Leaf shape and arrangement: Leaf: leaflets toothed from mid-blade to tip. Similar to low hop but larger leaves and flower heads than small hop clover (T. dubium Sibth). Distinguished from black medic by sessile (not stalked) attachment of central leaflets vs. petioled (stalked) attachment of black medic. Peduncles stout, stiff, straight often shorter than subtending leaves

Stolon/rhizome/roots ­ No stolon or rhizome; upright, hairy branched stems

Inflorecence - Bright yellow flowers 20-30 in loose clusters on long stalks attached at leaf axils; flowers turn brown and fall-back when mature

Black medic Medicago lupulina Hop clover T. agrarium same as large hop	Leaf, stipule Leaf oval, terminal leaflet has a slightly longer petiolule/stlked than the other two leaflets that occur close to the stem; prominent veins; wedge-shaped with spur on tip of each leaflets	Flower/fruit Yellow, cluster on a short stem, emerge from leaf axils, up to 50 individual flowers. Mature flower forms a tightly coiled black seedpod	Hair and stem Leaves and stems sparsely hairy; Square stem, hairy and branch from stem Stems are fairly erect and usually slightly branched
Low, small hop, smaller hop clover, suckling clover, lesser trefoil, least, sharmock Trifolium procumbens, dubium Sibth	Stipules obliquely ovate, one side broadly rounded , acute, sparsely pubescent. Terminal leaflet of each leaf is on a short stock/petiolule, leaflets with prominent veins	Bright yellow; larger than black medic and arranged in loose clusters; five to twelve individual flowers. Fewer flowers in the cluster than large hop clover	Has hairy, red, reclining stems, branches either creeping or upright
Large hop clover T. campestre Schreb the same as also aureum) Stipule linear-lancolate	Leaflets toothed from mid-blade to tip. Similar to low hop but larger leaves and flower heads than small hop clover (T. dubium Sibth). Distinguished from black medic by sessile (no stalked) attachment of central leaflets vs. petioled (stalked) attachment of black medic. Peduncles stout, stiff, straight often shorter than subtending leaves. Peduncles often exceeding the subtending leaves.	Bright yellow flowers 20-30 in loose clusters on long stalks attached at leaf axils. Larger leaves attached to hairy branched stems

McCarty L. B., J. W. Everest, D. W. Hall, T. R. Murphy and F. Yelverton. 2001. Color Atlas of Turfgrass Weeds. p. 165, 171, 172. Sleeping Bear Press. Chelsea, MI.

http://www.grzyby.pl/rosliny/gatunki/Trifolium_campestre.htm
http://www.bioimages.org.uk/index.htm
Large hop clover (Trifolium campestre Schreb.,)
Other common name: low hop clover
Small hop clover (Trifolium dubium Sibth.,)
Other common name: least hop clover
Life cycle: Winter annual

Distribution and Adaptation

• Throughout the United States
• Although three hop clovers have been documented, T. campestre and T. dubium are the ones frequently found in the northeast and southeast.
• Found on roadsides, waste places and pastures of low fertility levels.
• Adapted to droughty, infertile, and eroded soils; tolerate acid soils.

Morphology/Growth pattern

• Leaflets of hop clover are unlike most other clovers in that the center leaflet has a longer petiolule than the other two leaflets like species in the Medicago and Melilotus genera; seedheads are smaller than other clovers; globe-like inflorescence; petal yellow, turning brownish when dry; flower heads have 20 to 50 (fewer in T. dubium) yellowish flowers that turn light brown at maturity. The flowers of T. dubium are shaped like ³baseball bat² and arranged in loose clusters; while T. campestre individual flowers are more rounded in shape and flare at the tip.
• Flowers May - September
• Hop clovers (the three species) are low-growing cool-season annuals with yellow flowers in small heads

Use and Potential Problem

• Need to be utilized quickly due to a short season of production.
• Mainly used in a pasture crop because of low production.
• All three species have high nutritive values and are palatable.
• A welcome volunteer in pastures especially in absence of other legumes.
• Low yield over a short season

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