Trifolium is from the Latin tres meaning 3 and folium meaning leaf and refers to the 3 leaflets.
Persian Clover refers to its origin around Persia.
A hairless, low lying to somewhat erect annual clover with woolly burrs.
Two. Oval. Hairless. Round tips.
Round to kidney shaped.
Alternate. 3 leaflets.
Forms a rosette, usually 150-300 mm wide.
Stipules - Membranous to leafy, 6-13 mm long, broadly egg shaped with tapering tips. Partly fused to stem, the free part is triangular.
Petiole - As long or longer than leaflets.
Blade - Of leaflet, egg shaped, oblong or oval, with fine teeth, 6-17 mm long by 4-12 mm wide. Distinct veins. Hairless. Leaflet stalks are all the same length.
Low lying often with the ends bent upwards, branched, up to 800 mm long. Hairless.
Globular, at the ends of slender short stalks(peduncles) in leaf axils. 6-10 mm wide when in flower and increasing to 12-17 mm wide when in fruit.
Pea type. More or less stalkless.
Calyx - 2-3 mm long. 2 lipped. Tube 1-1.5 mm long, 13 veined, furry on the upper(adaxial) surface, hairless on the other side. Throat hairless inside. 5 narrow lobes that taper to a fine tip. The 2 upper(adaxial) lobes ~2mm long and spreading, the other 3 are 1-1.5 mm long and erect.
Petals - Pink to purple, 4-6 mm long. Limb of standard oblong, flat tipped to notched.
Stamens - 10 with 9 in a group.
Fruiting calyx bent back, papery, with a network of veins and the upper(adaxial) part swollen.
Pod, 2-2.5 mm long, elliptic to oblong in outline, enclosed within the calyx or burr.
Dark brown, oval, ~1.5 mm long.
Taproot. Has nitrogen fixing nodules on taproot and laterals.
Leaflets stalks are all the same length.
Stipules entire, distinctly veined, partly joined to the petiole.
Flower heads 4-10 mm across, not surrounded by bracts.
Calyx 13 veined, hairy, gibbous with the adaxial part inflated and chartaceous.
Calyx lobes of upper lip long, protruding from the fruiting calyx.
Pod enclosed in the calyx.
Adapted from Judy Wheeler, Flora of Perth.
Annual. Germinates autumn to spring. Flowers spring to early summer.
Has symbiotic rhizobia in nodules in the roots that fix atmospheric nitrogen.
October to November in Perth.
Seed Biology and Germination:
Commercial varieties are available.
Stubble can be allelopathic.
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
Europe, Mediterranean, Northern Africa, South Western Asia and the Middle East.
Introduced as a pasture and hay species.
ACT, NSW, QLD, SA, TAS, VIC, WA.
Naturalised in WA.
Loamy and clay loam red earths. Less common on sands, grey silts and heavy clays.
Capeweed, Annual Ryegrass.
Weed of lawns roadsides and disturbed areas.
Occasional weed of crops.
Closely related species may cause photo sensitisation in cattle and clover disease in sheep and occasionally bloat. No field cases have been reported for this species, possibly because of it low occurrence.
Remove stock from infested areas if toxicity suspected.
Management and Control:
10-20/m2 is expected to cause 10% yield loss in cereals.
Dicamba and sulfonylurea herbicides provide good control.
Prevent seed set for 5 years.
Exclude stock to prevent dispersal of seed and burrs.
Hand pull isolated plants in winter before flowering. For small infestations and grass dominant areas an annual application of 10 mL Tordon®75-D in 10 L water in early winter gives excellent control of existing plants and has residual activity to control seedlings.
In bushland, 200 g/ha Lontrel®750 or 50 g/ha Logran® applied in early winter provides reasonably selective control. Use 25 mL wetting agent plus 4 g Lontrel®750 or 1 g Logran® or 0.1 g metsulfuron(600g/L) or 0.1 g chlorsulfuron(750g/kg) in 10 L water for hand spraying when they are actively growing. Repeat annually for several years. Plant tall growing perennial species to reduce re-invasion.
Clovers are relatively tolerant to glyphosate, grazing and mowing.
Alsike Clover (Trifolium hybridum)
Arrowleaf Clover (Trifolium vesiculosum)
Balansa Clover (Trifolium balansae)
Berseem Clover (Trifolium alexandrinum)
Birdsfoot Trefoil (Trifolium ornithopodioides)
Bladder Clover (Trifolium spumosum)
Caucasian Clover (Trifolium ambiguum)
Cluster Clover, Ball Clover (Trifolium glomeratum) is a ground-hugging plant with broad leaflets, 5-22 mm long, and globular heads of pink flowers.
Crimson Clover (Trifolium incarnatum)
Cupped Clover (Trifolium cherleri)
Drooping flowered Clover (Trifolium cernuum)
Gland Clover (Trifolium glandulosum)
Globe Clover (Trifolium globosum)
Hop Clover(Trifolium campestre) is a sprawling plant with fairly broad leaflets, 4-15 mm long, and globular to ovoid heads of yellow flowers. The standard petal is not furrowed and it has 20-50 flowers in the head.
Hare's Foot Clover(Trifolium arvense) is an erect or sprawling plant with narrow leaflets 5-20 mm long and ovoid to shortly cylindric heads of white or pink flowers.
Kenya White Clover (Trifolium semipilosum)
Knotted Clover (Trifolium striatum)
Lappa Clover (Trifolium lappaceum)
Ligurian Clover (Trifolium ligusticum)
Narrow-leaved Clover (Trifolium angustifolium) is an erect plant with long narrow leaflets, 15-75 mm long, and cylindric heads of pink flowers.
Purple Clover (Trifolium purpureum)
Red Clover (Trifolium pratense)
Rose Clover(Trifolium hirtum) is a hairy plant with fairly broad leaflets, 10-25 mm long, and globular to semi-globular heads of pink to purple flowers.
Rough Clover (Trifolium scabrum)
Sea Clover (Trifolium squamosum)
Shaftal Clover (Trifolium resupinatum)
Slender Suckling Clover (Trifolium micranthum)
Star Clover (Trifolium stellatum)
Strawberry Clover (Trifolium fragiferum)
Subterranean Clover (Trifolium subterraneum) is a ground-hugging plant with broad leaflets, 6-22 mm long, and few-flowered heads of white flowers that form globular buried burrs.
Suckling Clover(Trifolium dubium) is a sprawling or ground-hugging plant with fairly broad leaflets, 4-12 mm long, and loose globular heads of yellow flowers.
Suffocated Clover (Trifolium suffocatum)
White Clover (Trifolium repens) is a ground-hugging plant with broad leaflets, 4-12 mm long, which often have a pale v-shaped band and globular heads of white flowers.
Woolly Clover(Trifolium tomentosum) is a sprawling plant with broad leaflets, 4-13 mm long and globular heads of pink flowers which become woolly with age.
Zigzag Clover (Trifolium medium)
Plants of similar appearance:
Shaftal clover (Trifolium resupinatum) is very similar to Woolly Clover (Trifolium tomentosum) but has a less hairy calyx ending in 2 obvious divergent lobes.
Medics, Trefoils, Soursob, Large flowered Wood Sorrel or Four-o'clock, Oxalis spp.
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne).
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia).
Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #1013.22.
Marchant et al (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P305-306.
Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne).