Johnson Grass
Sorghum halepense

Family: Poaceae or Gramineae

What it is like

Sorghum halepense is a PERENNIAL growing to 2 m (6ft) by 1.2 m (4ft in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 8. It is in flower from August to October, and the seeds ripen from September to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Wind. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

Height (m): 2

Where it is found

Dry open habitats.

Europe to Asia.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 3

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.

Seed: includes nuts, cereals, peas and beans.

Medicine

Rating: 1

The seed is demulcent and diuretic.

Demulcent: Soothes, lubricates and softens irritated tissues, especially the mucous membranes.

Diuretic: Acts on the kidneys, promoting the flow of urine.

Other

Rating: 3

The plant is a potential source of biomass with yields of up to 19 tonnes per hectare.

Biomass: Provides a large quantity of plant material that can be converted into fuel etc.

How it is grown

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. Temperatures below 13°C tend to inhibit flowering. For best results, it requires a warm sunny position. The plant is reported to tolerate an annual precipitation in the range of 9 to 429cm, an annual temperature in the range of 8.3 to 27.8°C and a pH of 4.9 to 8.2. This species is not very winter hardy, tolerating occasional temperatures down to about -5°c so long as the soil is not too wet. It is best adapted to warm humid summer-rainfall areas in the subtropics, not growing well in strictly tropical areas. A very aggressive plant, spreading freely at the roots and only suitable for large areas. It is a parent of the cultivated Sorghum (S. bicolor). Classified as a short day plant, it does not flower if the daylight hours exceed about 13 hours per day.

Propagating it: Seed - sow April in a greenhouse and only just cover the seed. Germination should take place within 2 weeks. Prick out the seedlings into individual pots once they are large enough to handle and plant them out after the last expected frosts. Division in mid spring as the plant comes into new growth. Larger divisions can be planted out direct into their permanent positions. We have found it best to pot up the smaller divisions and grow them on in a lightly shaded position in a cold frame, planting them out once they are well established in the summer.

Best place to grow: Cultivated Beds;

Habit: Perennial

Hardiness: 7-10

Growth: Fast

Soil: Light (sandy), medium, heavy (clay)

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

The pollen can induce hay fever.

Its other names

Local names

Synonyms

Holcus halapensis.