Trifolium hirtum All.

Symbol: 
TRHI4
Group: 
Dicot
Family: 
Fabaceae
Uses: 
Pasture
Soil Improvement (Green manure)
Soil Protection (Cover Crop)
Description: 

Rose clover is a herbaceous, self-regenerating winter annual legume that originated in the Mediterranean region. It has a semi-erect growth habit similar to crimson clover, with somewhat later growth period in mid-spring. It has two main uses, as a pasture species often combined with sub clover, medics and serradella, and for stabilizing degraded areas associated with mining or road building. Also used as a vineyard cover crop.

Identification Characteristics

Type: 
Legume
Growth Season: 
Cool
Identification Characteristics: 

Inflorescence is a globular terminal head with 20-40 lavender-colored flowers in each head.

Leaves are pubescent, with obovate, pale green leaflets. Even though cultivars can have different leaf markings, they usually have pale crescents bordered by brownish-red lines.

Stems are 3-24 inches (8-60 cm) tall and densely pubescent. Stipules have green veination and are rounded, coming to a point.

Rose clover is deeper rooted than most annual clovers, with roots to more than 6 feet (2 m) in deep soils.

Seeds are smooth, slightly compressed, cream colored, approximately 2 mm long and weigh 3-4 mg, with about 250,000 seeds/kg (114,000/lb).

Growth Habit and Stand Life

Semi-erect growth habit. Winter annual.

Life Cycle: 
Winter annual

Yield Potential and Production Profile

Establishment: Seeds are drilled 0.2-0.4 inches (0.5-1.0 cm) deep in autumn, using 2.7-6.3 lb/a (3-7 kg/ha) in a mix with sub clover, barrel medic, alfalfa, serradella, and/or perennial grasses. Use group C inoculant and lime pellet if sown into acid soil or mixed with fertilizer. Ensure adequate amounts are P, S, and Mo are present by fertilizing to soil test recommendations [typically 90-134 lb/ac (100-150 kg/ha) superphosphate].

Management: Even though it is suited to grazing and tolerates close grazing, rose clover needs careful spring management to prevent overgrazing which will reduce seed production. Seed yield is approximately 225-625 lb/a (250-700 kg/ha), similar to subterranean clover. Stands should be grazed before fall rains to allow hooves to press seeds into the soil. Superphosphate and sulfur fertilizers should be applied every two to three years. For vineyards, occasional mowing in spring and early summer and fertilizer applications of 1-2 tons/acre (2.24-4.5 MT/ha) of compost annually are recommended.

Cultivars

There are several cultivars varying in their maturity, rainfall required, cold tolerance, and optimal soil conditions:

  • Sirint is an upright growing, very early flowering cultivar suited to lower rainfall regions.
  • Olympus has a prostrate growth habit and flowers about 10 days later than Sirint.
  • Kondinin is has a semi-erect growth habit and flowers about 10 days later than Olympus; it has little cold tolerance or winter dormancy.
  • Hykon is the most readily available cultivar; it tolerates acidic, poor fertility, and dry soils; is early maturing – 7 to 10 days earlier than Kondinin, suited to lower rainfall areas.
  • Wilton is widely adapted to elevations below 3000 feet, and has good seed production.
  • Monte Frio tolerates cold and dry conditions, persisting better than subterranean clover.

Management Level Required

Suitable Management Level: 
High
Medium

Climate and Soil Suitability Zones

Climate Tolerances: 

Rose clover is grown widely in California (except for the coastal fog belt), central Oklahoma, and north-central Texas. It will grow in areas too dry for sub clover and too acid for medics.

Native to the Mediterranean region and thus suitable for regions which have 16 to 30 inches (400 to 750 mm) of annual rainfall and summer-dry conditions. Although it tolerates frosts, it is not tolerant of cold winters; suitable in USDA Plant Hardiness Zones 6b-10b [Average Annual Extreme Minimum Temperature of -5 to 0 °F (-21 to -18 °C)] and July mean maximum temperature of 80-90 °F (27-32 °C).

Soil Tolerances: 

Suited well-drained, sandy loams through clay loam moderately-drained soils. pH suitability is strongly-acid to moderately-alkaline soils (pH = 5.0-8.3). Tolerates neutral sodic soils (3-5 dS/m) and short periods (3 days) of waterlogging.

Quantitative Tolerances: 

Rose Clover Suitability Tolerance Values

Suitability Class

Jan Min (°C)*

July Max

(°C)

Annual Precip (mm)**

Soil pH***

Soil Drainage†  

Soil Salinity (dS/m)#

Well-suited

-17

27

750

5.8-7.3

MWD-WD

1-2

Moderately suited

-19

29

600

5.5-7.5

SPD-SED

2-3

Marginally suited

-21

32

400

5.0-8.0

PD-SED

3-4

*Low temperature: USDA Plant Hardiness Zones: 6b-10b

   Rooting: Roots to 6 feet (2 m).

*** Soil pH: Strongly Acid to Moderately Alkaline: 5.0-8.3. 

† Soil drainage: Tolerates water-logged soils. Soil drainage class abbreviations: 1=VPD, very poorly drained; 2=PD, poorly drained; 3=SPD, somewhat poorly drained; 4=MWD, moderately well drained, 5=WD, well drained; 6=SED, somewhat excessively drained; 7=ED, excessively drained. Percent relative yield for rose clover for the classes 1-7: 15, 40, 75, 100, 100, 55, 20, respectively.

# Soil salinity: Mildly saline soils (3-5 dS/m)

Quality and Antiquality Factors

Quality Factors: 

High quality forage suitable for grazing, hay, or silage. High seed coat impermeability. Protein above 20% if harvested before bloom stage. Beef cattle liveweight gain from grazing rose clover pastures is slightly higher than for crimson or arrowleaf clovers (3.5, 3.2 and 3.3 lb/day, respectively). Nitrogen fixation of rose clover provides 90 lb N/ac/year (~100 kg/ha/year). Few disease or insect pests.

Anti-quality Factors: 

Can cause bloat in cattle on pure legume stands. Negligible amounts of estrogen (no infertility issues detected in sheep). Ingestion of old flower heads may cause development of an indigestible mass in the abomasum of cattle and wool contamination in late-dropped lambs. No major insect pests or diseases.

Species Selection Characteristics

Annual Precipitation (inches): 
16 to 20
20 to 24
24 to 28
28 to 32
Plant Hardiness Zones (cold tolerance): 
6b
7a
7b
8a
8b
9a
9b
10a
10b
Heat Zone (July Mean Max Temperature): 
77 to 80 °F
80 to 84 °F
84 to 88 °F
88 to 92 °F
Soil pH Tolerance: 
Strongly acid, 5.1–7.3
Moderately acid, 5.6–7.3
Moderately acid to moderately alkaline, 5.6–8.4
Slightly acid to moderately alkaline, 6.1–8.4
Near neutral, 6.1–7.3
Soil Drainage Tolerance: 
somewhat poorly drained
moderately well drained
well drained
somewhat excessively drained
Flooding Tolerance: 
3-6 days
Soil Salinity Tolerance: 
Moderately tolerant, 3–6 dS/m

Image Gallery

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Resources

Publications: 

Bailey, E.T. 1967. The history, characteristics, and potential of Kondinin rose clover. J. Agric. Western Australia 9:372-373.

Dear, B.S. 2002. Rose clover. AgFacts P2.5.38. NSW Agric. https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0015/165300/p2538.pdf  Retrieved April 15, 2018.

Dyer, Dave. 2005. Rose Clover Plant Guide. USDA NRCS.  https://plants.usda.gov/plantguide/pdf/pg_trhi4.pdf Retrieved April 15, 2018.

Loi, Angelo. 2009. Rose clover. Fact Sheet, Pastures Australia.  https://keys.lucidcentral.org/keys/v3/pastures/Html/Rose_clover.htm Retrieved April 15, 2018.  

Love, R. M. 1985. Rose Clover. Agron. Monogr. 25 chpt. 24, pp. 535-546. ASA, CSSA, SSSA, Madison, WI. 

Pasture Genetics. Sardi Rose Clover. http://pasturegenetics.com/seed/sardi-rose-clover/?pdf=2159 Retrieved April 15, 2018.

Swearingen, J., C. Bargeron. 2016. Rose clover. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health. https://www.invasiveplantatlas.org/subject.html?sub=18778 Retrieved April 15, 2018.

Witham, Carol W. 20014. Rose clover photos. CalPhotos 0563 and 0564. https://calphotos.berkeley.edu Retrieved April 15, 2018.

Volesky, J. D., D. P. Mowrey, and Smith, G. 1996. Performance of Rose Clover and Hairy Vetch Interseeded into Old World Bluestem. J. Range Mgmt. 49(5):448-451. doi:10.2307/4002928