Calopogonium sericeum (Benth.) Chodat & Hassl.
Stenolobium caeruleum Benth.
Calopogonium caeruleum is a large climbing shrub producing twining, perennial stems up to several metres long that become woody with age and root at the nodes when in contact with moist soil[
]. The plant scrambles over the ground, twining into nearby shrubs[
The plant is widely grown throughout the humid tropics as a green manure crop[
]. It is rather showy when in flower, but is usually considered too vigorous to grow as an ornamental.
Eastern tropical S. America, north through C. America to Mexico and the West Indies.
Moist thickets, bushy, rocky areas and light forests[
]. Dry to wet thickets; at elevations up to 1,800 metres[
|Other Uses Rating||
|Cultivation Status||Cultivated, Wild
Calopogonium caeruleum is adapted to the humid tropics but it is also somewhat drought-tolerant[
]. It grows better in cooler conditions than centro (Centrosema pubescens) and in the elevated tropics can grow up to an altitude of about 800 metres[
]. It grows best in areas with a mean annual rainfall of 1,000 - 3,000mm, but will persist in environments with as little as 700mm[
]. It prefers environments with daily temperatures ranging from 18 - 25°c, tolerating 10 - 32°c[
Succeeds in most soils if they are well drained[
]. Plants prefer a sunny position, but are very tolerant of shading[
]. Plants can succeed in acid soils with a pH as low as 4.0[
Calopogonium caeruleum has been widely planted throughout the humid tropics, and has escaped from cultivation and become naturalised in many areas[
]. It has considerable weed potential, often smothering desirable grasses and other understorey species[
]. It has invaded seasonally wet tropical environments[
The seed can remain viable in the soil for several years[
When growing in the humid tropics it flowers indeterminately through the first wet season, producing seed into the dry season[
]. It is capable of producing moderate amounts of seed even in its first year[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
Plants can be grown as a green manure crop. The plant gives good soil cover; builds up soil fertility through its leaf fall and nitrogen production; and can be used to smother weeds such as Imperata cylindrica[
]. It is grown in plantations where it can be fully productive in full sun and up to 40% shade, it grows well in mature coconut plantations where there is 30 - 40% shade, and will still do fairly well in heavy shade[
]. It is slower to establish than Calopogonium mucunoides and Pueraria phaseoloides and may take 20 months to achieve a complete cover.
The plant is used by laundresses in El Salvador to take dirt out of clothes whilst rubbing them[
]. Bunches of the tough stems are used by washerwomen for rubbing the dirt from clothing, in order to save soap[
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 this species with Pueraria phaseoloides at 1-1.5 and 5-7.5 kg/ha seed, respectively.
Plants 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.
As a green manure crop, can be established by broadcasting into upland rice following the final weeding. Mid-season plantings may reduce rice yields[
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