Calopogonium caeruleum

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Flowers - inflorescence is an elongated raceme.

Immature pods and seeds.

Foliage - leaves are trifoliolate with long petioles.

A twining perennial suitable for groundcover and green manure.

A groundcover under rubber trees.

Low palatability leads to dominance in mixed pastures.

From:‘t Mannetje, L. and Jones, R.M. (1992) Plant Resources of South-East Asia No. 4. Forages. (Pudoc Scientific Publishers, Wageningen, the Netherlands). © Prosea Foundation.

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Scientific name

Calopogonium caeruleum (Benth.) Sauvalle


Calopogonium coeruleum (Benth.) Sauvalle
Calopogonium coeruleum (Benth.) Sauvalle var. glabrescens (Benth.) Malme
Calopogonium sericeum (Benth.) Chodat & Hassler
Calopogonium sericeum (Benth.) Chodat & Hassler var. villicalyx Chodat & Hassler
Stenolobium caeruleum Benth.


Family: Fabaceae (alt. Leguminosae) subfamily: Faboideae tribe: Phaseoleae subtribe: Glycininae. Also placed in: Papilionaceae.

Common names

bejuco culebra, bejuco de lavar, calopog"nio-perene, canela-araquan, chorreque, cip¢-araquan, cip¢-de-macaco, feijao-bravo, feijao-de-macaco, feijaozinho-da-mata, haba de burro, cama dulce.

Morphological description

A twining, perennial legume, with stems up to several metres long, becoming woody with age, rooting at nodes when in contact with moist soil;  may be hairy or nearly hairless.  Leaves trifoliolate with a long petiole (to 16 cm);  leaflets elliptical, ovate or rhomboid ovate, 6-9 cm x 4-6 cm.  Lateral leaflets are oblique, pubescent above, velvety pubescent below.  The inflorescence is an elongated, raceme, up to 50 cm long with many flowers consisting of a bell-shaped, 5-lobed calyx and blue or violet corolla, about 1 cm long.  The furrowed rachis is covered with short hairs.  Pod linear-oblong, 4-8 cm x 0.8 cm, straight or curved, impressed between the seeds, pubescent.  Seeds are shiny-brown in colour, 4-5 mm across, orbiculate in shape;  4-8 seeds/pod .


Native to:
Occurs naturally throughout tropical America, from Mexico and the Caribbean islands in the north, to northern Argentina in the south.

Widely planted and naturalised throughout the humid tropics.


Green manure crop providing large amounts of dry matter through leaf fall.  Cover crop, especially in tropical tree plantations.  Excellent ability to smother weeds and provide soil cover.


Soil requirements

Adapted to a wide range of soil textures and soils with pH as low as 4.0.  Grows best on well-drained soils.  Despite its tolerance of low pH , it responds to P fertiliser and lime on acid infertile soils.


Adapted to the humid tropics with annual rainfall of 1,000-3,000 mm, but will persist in environments with as low as 700 mm annual rainfall.  More drought tolerant than C. mucunoides and Pueraria phaseoloides .


Prefers tropical environments with 25ºC maximum and 18ºC minimum day temperatures, with outer limits of 32ºC maximum and 10ºC minimum.  Will outperform C. mucunoides and Centrosema molle in cool conditions.


Productivity is relatively constant at 60-100% light transmission.  Will grow productively in mature coconut plantations (60-70% PAR ), and is tolerant of heavy shade.

Reproductive development

In the humid tropics, flowers indeterminately through the first wet season, producing seed into the dry season.  Capable of producing moderate amounts of seed in the establishment year.


Rarely grazed by cattle and may dominate pastures unless controlled.


No information available.


Guidelines for the establishment and management of sown pastures.


Usually established from seed, sowing into a cultivated seedbed at the beginning of the wet season.  Establishment can be slow and may be improved by addition of P fertiliser and lime, and by controlling weeds.  Current recommendations for cover crop under oil palm in southeast Asia are to seed C. caeruleum and Pueraria phaseoloides at 1-1.5 and 5-7.5 kg/ha seed, respectively.
Can be established by stem cuttings but low success rates (5% of cuttings) are common.  Using older stem material and treating stems with root-promoting hormones can improve success rates.
Slower to establish than C. mucunoides and Pueraria phaseoloides and may take 20 months to achieve a complete cover.
As a green manure crop, can be established by broadcasting into upland rice following the final weeding.  Mid-season plantings may reduce rice yields.


Despite its acid soil tolerance, best growth of C. caeruleum on an acid, infertile soil in Indonesia was achieved with application of 10.8 t/ha lime and 315 kg/ha triple superphosphate.  The critical levels of Al saturation and available P (Olsen P) of the soil for C. caeruleum were 6.8% and 7 ppm P, respectively.  Growth declined at higher Al saturation percentage and lower P concentration.

Compatibility (with other species)

Companion grasses are grazed in preference to C. caeruleum , resulting in the dominance of this unpalatable legume .
In species mixtures, C. caeruleum eventually dominates, especially under heavy shade.

Companion species

Legumes:  Planted as a cover crop in southeast Asian plantation agriculture, often in a species mixture with one or more of the species C. mucunoides , Centrosema molle , Pueraria phaseoloides and Desmodium ovalifolium .

Pests and diseases

The fungal pathogens Cercospora leafspot, anthracnose and Rhizoctonia foliar blight have been identified on C. caeruleum in Colombia.

Ability to spread

Will spread from stolons under favourable conditions, rooting at the nodes.

Weed potential

Considerable weed potential.  Weed of tropical plantation crops, often smothering desirable grasses and other understorey species.  Has invaded seasonally wet tropical environments.

Feeding value

Nutritive value

Top growth has moderate to high nutritive value and contains 13-23% CP .  In Nigeria, 6-month regrowth had in sacco DMD of 48-55%, CP 13-16%, Ca 2.0-2.25%, P 0.2-0.3%;  dry-season values were somewhat lower.  In Colombia, leaf material of 6 months old plants contained 18% CP, 1.15% Ca, 0.20% P, 49% IVDMD and no condensed tannins.


Very low palatability to ruminant livestock.  Over an 8-month period of grazing by sheep in a rubber plantation in Malaysia, Paspalum conjugatum and other forages rapidly decreased in contribution to DM as they were grazed in preference to C. caeruleum which increased its contribution from 5 to 40%.
Palatability improves to a limited extent during the dry season, although intake generally remains extremely low.  There may be potential to select for improved palatability from within the CIAT germplasm collection.
Ensiling may improve palatability .


Does not contain compounds toxic to livestock.

Production potential

Dry matter

One of the most productive herbaceous legumes, generally producing yields of 3-7 t/ha/year DM.  Produced DM yields of 1-1.5 t/ha/year under mature oil palm (10% light transmission), out yielding a wide range of common herbaceous legumes.
As a green manure crop/mulch , leaf fall from uncut C. caeruleum can be as high as 7 t/ha/year DM.  In Nigeria, it had the second highest green manure effect on maize yield among 12 legumes tested, providing an N equivalent of about 90 kg/ha.

Animal production

Sheep grazing pastures dominated by C. caeruleum under 7-year-old mature rubber at Selangor, Malaysia, gained 99 g/head/day liveweight at a stocking rate of 2 sheep/ha (72 kg/ha/year).  The forage availability was <0.6 t/ha.  Under immature rubber, early high levels of forage production (2.2 t/ha) supported liveweight gain of 84 g liveweight/head/day at a stocking rate of 14 sheep/ha (429 kg/ha per year).  Grazing decreased the proportion of palatable species and increased the proportion of C. caeruleum from 5% to 40%.
Cattle grazing open guinea grass (Panicum maximum )-C. caeruleum pastures gained 0.5 kg/head/day over the first 2 years of grazing, but liveweight gains declined to 0.2 kg/head/day as calopo became dominant over the subsequent year.


No breeding programs are currently being conducted.
In field and pot experiments at Quilichao, Colombia, most C. caeruleum accessions showed poor adaptation to acid infertile soils and drought and had problems with diseases, pests and acceptance by cattle, but a few accessions showed some promise, indicating agronomic and forage quality variation within the species.

Seed production

Produces seed in the first year of growth.  In southern Thailand, seed production was increased by basal fertiliser application of monocalcium phosphate, gypsum, potassium sulphate, magnesium, zinc, copper, cobalt and molybdenum at the rates of 205, 40, 330, 60, 14, 4, 0.6 and 1.2 kg/ha, respectively.  Seed yield increase was attributed to improved plant survival and increased number of pods per plant.

Herbicide effects

A range of herbicides applied at a spray volume of 400 litres/ha was evaluated for control of weeds during the establishment of C. caeruleum sown 3-4 cm deep as a cover crop .  Oxyfluorfen at 0.3 kg/ha applied in the rows immediately after sowing C. caeruleum caused some initial injury but the effect was short-lived.  No damage occurred with the herbicides diphenamid at 3 kg/ha, neburon at 2 kg/ha, napropamide at 2 kg/ha, alachlor at 0.5-1 kg/ha and metolachlor at 2 kg/ha.  In a separate experiment, imazethapyr at 15-400 g ai/ha provided excellent control of weeds and facilitated rapid establishment of Pueraria phaseoloides and C. caeruleum in oil palm plantations.
Poor control of C. caeruleum (as a weed) was achieved when mature plants were sprayed with metsulfuron at 10 g/ha and 20 g/ha, glyphosate at 10 g/ha and 20 g/ha, paraquat at 560 g/ha and diuron + paraquat at 560 + 560 g/ha.  However, combinations of metsulfuron + glyphosate or paraquat at 10 + 560 g and 20 + 560 g achieved effective control 4 weeks after application.
Fosamine at 0.75-1 kg ai/ha provided excellent suppression of C. caeruleum for 8-12 weeks to reduce competition in planting sites for rubber and oil palm.  Efficacy depended on the vigour of the calopo at the time of spraying.



Other comments


Selected references

Chen, C.P. and Chee, Y.K. (1992) Calopogonium caeruleum . In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages. pp. 71-72. (Pudoc Scientific Publishers, Wageningen, the Netherlands).
Chong, D.T., Tajuddin, I., Samat, A.M.S., Stür, W.W. and Shelton, H.M. (1997) Stocking rate effects on sheep and forage productivity under rubber in Malaysia. Journal of Agricultural Science, 128, 339-346.
Hardjono, A. and Warsito, T. (1990) The effect of lime and P fertilizer on the growth of Calopogonium caeruleum . II. Field experiment. Menara Perkebunan, 58, 70-73.
Keller-Grein, G. (1984) Untersuchungen über die Eignung von Herkünften verschiedener wenig bekannter Leguminosenarten als Weidepflanzen für südamerikanische Savannengebiete. Göttinger Beiträge zur Land- und Forstwirtschaft in den Tropen und Subtropen, Vol. 5 . University öf Göttingen, Germany.
Middleton , C.H. and Mellor, W. (1982) Grazing assessment of the tropical legume Calopogonium caeruleum . Tropical Grasslands, 16, 213-216.
Muhr, L., Peters, M., Tarawali, S.A. and Schultze-Kraft, R. (1999) Forage legumes for improved fallows in agropastoral systems of subhumid West Africa: I. Establishment, herbage yield and nutritive value of legumes as dry season forage . Tropical Grasslands, 33, 222-233.

Internet links



Country/date released


No cultivars of C. caeruleum have been officially released to date.          

Promising accessions

Promising accessions



CPI 28107 Australia Poor palatability to cattle in grazing trial in northern Australia.
CIAT 7471, 8130, 8511, 8512, 8702 Colombia High yield, highest palatability among 38 accessions.