Cenchrus polystachios

Cultivation Details

A plant of the moist tropical zone, preferring lowland areas but also found at elevations up to 2,400 metres - it is rarely found growing outside the tropical region. It grows best in areas where annual daytime temperatures are within the range 32 - 35°c, but can tolerate 12 - 40°c^[1]. It prefers a mean annual rainfall in the range 1,000 - 2,000mm, but tolerates 750 - 3,000mm^[1]. Grows best in a sunny position or in light shade^[1], though it has persisted when growing under 80% shade^[2]. It succeeds in a wide range of soils, preferring sandy soils and tolerating low fertility^{[2, 1]}. It succeeds in highly phosphate-deficient nigrescent soils in Fiji^[2]. Prefers a pH in the range 5 - 6.5, tolerating 4.4 - 8.5^[1]. Established plants are tolerant of short-term seasonal inundation, and also of drought^[1]. Originally native from Africa to India, the plant has spread through human activity and has become naturalized in many other areas of the tropics. It is declared a noxious weed in some areas^[3]. The spreads are light and fluffy, they are spread readily by wind, attachment to animals, clothing etc. They also survive the annual burning that occurs in some areas - they then germinates rapidly and can smother other seedling plants. As a fire disclimax, it becomes the dominant species in a good deal of the mountainous land in Thailand and Fiji^[2]. It causes major problems in the Northern Territory of Australia, where it has greatly increased the amount of flammable material in the wooded savannah ecosystem, leading to greater devastation from bushfires^[4]. Dry matter yields may be between 5 - 10 tonnes per hectare^[1].