Macroptilium atropurpureum

Cultivation Details

The plant grows well from the subtropics with fairly cold winters to the seasonal tropics, succeeding in semi-arid areas but not doing so well in humid areas; it can be found at elevations up to 2,900 metres. It grows best in areas where annual daytime temperatures are within the range 21 - 32°c, but can tolerate 13 - 36°c^[1]. When dormant, the root system can survive temperatures down to about -8°c, but young growth can be severely damaged at -1°c^[1]. It prefers a mean annual rainfall in the range 650 - 1,800mm, but tolerates 200 - 2,800mm^[1]. Requires a sunny position for best growth, tolerating light shade^[1]. Tolerant of a range of well-drained soils, other than heavy clays,and growing well in soils of moderate fertility and tolerating poor fertility^{[1, 2]}. Succeeds in dry soils and very tolerant of drought once established^{[3, 1]}. Prefers a pH in the range 6 - 7.5, tolerating 4.5 - 8.5^[1]. Plants grow vigorously from seed - in weeded beds they can flower and produce seed in their first year, but when grown amongst other plants they usually take longer^[4]. The plant generally lives from 1 - 10 years^[4]. 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^[3].