Macroptilium atropurpureum
purple bush-bean
Overview
Macroptilium atropurpureum is a trailing perennial legume with stems extending 6.5-13 feet (2-4 m) across the ground and twining over low supports. Leaves are trifoliolate, the leaflets ovate and often shallowly lobed, 0.8-2.8 inches (2-7 cm) long, green above and covered with silvery-white hairs beneath. Deep purple-black flowers, each 0.6-0.8 inch (1.5-2 cm) long, appear in small clusters on slender stalks 4-10 inches (10-25 cm) long through the warm months. Flowers are followed by linear pods 2-3.5 inches (5-9 cm) long, each holding up to 12 mottled brown seeds that scatter when the pod splits and twists. A taproot reaching 5-6.5 feet (1.5-2 m) supports growth through dry periods, and stems root at the nodes where they contact moist soil. Foliage is damaged by light frost and the plant is killed by hard freezes, which restricts persistence to frost-free and near-frost-free climates. In cultivation it is grown as a pasture and cover legume, and it has naturalized along roadsides and in disturbed ground in many subtropical regions, where it climbs over low vegetation.
Native Range
Native to tropical and subtropical America, from southern Texas and Mexico south through Central America to Argentina. Grows in grassland, open woodland, and disturbed ground from sea level to about 6,500 feet (2,000 m).Suggested Uses
Planted as a forage and cover legume in pastures and on slopes for nitrogen fixation and soil stabilization, sown or spaced to cover open ground. Used on embankments where trailing stems bind loose soil. Spreads by rooting stems and self-sown seed, and is restricted in some regions where it has naturalized.How to Identify
Appearance
Size & Dimensions
Height1' - 2'
Width/Spread6'6" - 13'
Bloom Information
Flowers through spring and summer in frost-free climates, mainly November to April in the southern hemisphere and May to September in the northern hemisphere. Each raceme carries a few flowers that open over several weeks. Flowering slows in cool weather and stops once frost kills the foliage.
Detailed Descriptions
Foliage Description
Green above, silvery-white beneathGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight