Botanical Name: Sorghum halepense
Species: S. halepense
Common Name: Johnson Grass
Habitat:Sorghum halepense is native to western and northern Africa; through Asia to Pakistan and India. Iy grows on moist areas on river banks, in clay soils and wet sandy soils.
Johnson grass is an erect grass, with culms from 60-290 cm in height. It forms an extensive underground root systems.
The plant has an edible seed that is occasionally eaten. It also has medicinal uses and is a potential biomass.
It grows best in areas where annual daytime temperatures are within the range 24 – 32°c, but can tolerate 15 – 36°c. Temperatures below 13°c tend to inhibit flowering. When dormant, the plant can survive temperatures down to about -7°c, but young growth can be severely damaged at -1°c. It prefers a mean annual rainfall in the range 500 – 750mm, but tolerates 450 – 1,500mm.
Prefers a warm sunny position. An easily grown plant, it succeeds in ordinary garden soil. It is adapted to a wide range of soil types, including upland clay, but seems to do best on porous fertile lowlands and river bottoms. It does well on heavy clay soils of relatively high fertility and water holding capacity. Prefers a pH in the range 6 – 6.8, tolerating 4.9 – 8.2.
Edible Uses: Seed – raw or cooked. It can be used whole in a similar manner to rice or millet, or it can be ground into a flour and used as a cereal in making bread, cakes etc.
Medicinal Uses: The seed is demulcent and diuretic.
Other Uses: The grass plant is a potential source of biomass with yields of up to 19 tonnes per hectare.
Known Hazards : The pollen can induce hay fever.