Chapter 3: Clover and Some Relatives

ROSE CLOVER³⁴Trifolium hirtum All., family Leguminosae
Rose clover is grown primarily in California, where it is used for seeding brush burns, cleared brushland, and dryland pasture. It will grow in dry "sterile" fields, on slopes, sandy steppes, or roadsides, and in waste places. Cattle and sheep, as well as such wildlife as deer, doves, and quail feed upon it even when it is completely dried up (Arkley et al. 1955, Holland 1964, Love and Sumner 1952, Williams et al. 1957).
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³⁴ See "Clovers, General."

Plant:
Rose clover is a reseeding annual winter legume. The leaflets usually have a small reddish mark near or slightly above the center (Strang and Broue 1958). The leaf stalks are 1/2 inch to 2 inches long. The seeds germinate with the first substantial fall rain and the plant grows slowly as a rosette of leaves until late winter. Then, as spring temperatures rise, it grows rapidly into an upright many-branched plant 3 to 18 inches tall. It blooms and sets seed in May. The plant then becomes dry and casts its seeds, which ripen 4 to 6 weeks after flowering starts. The seeds remain dormant in the soil until fall rains begin (Bailey 1966, Williams and Leonard 1959). Rose clover provides a high-quality forage pasture under a wide variety of climatic conditions in California. Plantings succeed in areas with as little as 10 inches of rainfall. Foliage of rose clover is much less profuse than most other clovers. It has the ability to produce some seeds under extremely unfavorable conditions (fig. 170).

[gfx] FIGURE 170. - Rose clover in bloom.

Inflorescence:
The pink flower head of rose clover is spherical, about three- quarters of an inch across, and profusely covered with stiff white hairs. These blossoms are highly attractive to bees for both nectar and pollen. When a floret is visited by a bee, the staminal column protrudes, then withdraws after the bee departs. From four to six bees per square yard have been seen on this plant. There is one seed per floret, and there are 40 florets per head.

Pollination Requirements:
Bohart (1960*) stated, "In California, honey bees are sometimes placed by fields of rose clover to ensure pollination, but apparently the practice is not based on any known requirement." This would indicate that experience may have convinced growers that, despite lack of experimental evidence, bee pollination is beneficial to this crop. The subject should be explored and the true pollination requirement of this important western forage determined.

Pollinators:
Evidence indicates that honey bees can be satisfactory pollinators of rose clover. Pollination Recommendations and Practices There are no recommendations for the use of pollinating insects on rose clover, although the reference by Bohart (1960*) indicates that growers believe they obtain some benefit from bee pollination.

LITERATURE CITED:
ARKLEY, R. J., HELPHINSTINE, W. N., and WILLIAMS, W. A.
1955. RANGELAND FORAGE ALMOST TREBLED BY SEEDING ROSE CLOVER AND USE OF SULFUR-BEARING FERTILIZERS. Calif. Agr. 9(8): 15-16.

BAILEY, E. T.
1966. ROSE CLOVER, DESCRIPTION, USE AND VARIETAL DIFFERENCES OF ROSE CLOVER IN WESTERN AUSTRALIA. West. Austral. Dept. Agr. Jour. (ser. 4) 7(4): 170-172,175.

HOLLAND, A. A.
1964. CLOVER ESTABLISHMENT IN NORTHERN CALIFORNIA. Calif. Agr. 18(7): 15.

LOVE, R. M., and SUMNER, D. C.
1952. ROSE CLOVER, A NEW WINTER LEGUME. Calif. Agr. Ext. Serv. Cir. 407,11 pp.

STRANG, J., and BROUE, P.
1958. ROSE CLOVER - A PROMISING SPECIES. Agr. Gaz. N.S. Wales 69(7): 368-369.

WILLIAMS, W. A., and LEONARD, O. A.
1959. EFFECT OF 2, 4-D ON THE GROWTH, SEED PRODUCTION, AND SEED VIABILITY OF ROSE CLOVER. Agron. Jour. 51: 383.

______LOVE, R. M., and BERRY, L. J.
1957. PRODUCTION OF RANGE CLOVERS. Calif. Agr. Expt. Sta. Cir. 458,19 pp.