Common Name: Slender Amaranth

General Information

Amaranthus blitum is a vigorous, annual plant producing erect to prostrate stems 6 - 90cm long[]. The stems can be simple or branched, sometimes radiating from base and forming mats[, ].
The edible leaves and seeds are sometimes gathered from the wild and used locally. The plant, especially the form Amaranthus blitum oleraceus, is often allowed to grow as a weed and is occasionally cultivated as a vegetable[, , ]. The leaves are sold in local markets[].
The plant has become a weed in many areas of the world outside its original range. It is classified as 'Invasive' in many Pacific Islands[].

Known Hazards

No members of this genus are known to be poisonous, but when grown on nitrogen-rich soils they are known to concentrate nitrates in the leaves. This is especially noticeable on land where chemical fertilizers are used. Nitrates are implicated in stomach cancers, blue babies and some other health problems. It is inadvisable, therefore, to eat this plant if it is grown inorganically.

Botanical References

,

Range

A cosmopolitan weed, spread through the Temperate and Tropical zones

Habitat

A cosmopolitan weed growing on waste ground[, ].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	0.70 m
Pollinators	Wind, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Semi-cultivated, Wild

Cultivation Details

Often cultivated, especially the form oleraceus, the plant succeeds from the temperate zone through to the tropics. It grows best in areas where annual daytime temperatures are within the range 21 - 27°c, but can tolerate 18 - 32°c[]. It can be killed by temperatures of 4°c or lower[]. It prefers a mean annual rainfall in the range 1,200 - 1,500mm, but tolerates 200 - 2,700mm[].
Prefers a well-drained fertile soil in a sunny position[]. Requires a hot sheltered position if it is to do well[]. Prefers a pH in the range 5.5 - 7, tolerating 4.3 to 7.5[].
Plants are particularly susceptible to attacks by leaf-chewing insects[].
Plants should not be given inorganic fertilizers, see notes above on toxicity.
This plant was cultivated by the ancient Romans and Greeks for its edible leaves, there are some named varieties[].
Most if not all members of this genus photosynthesize by a more efficient method than most plants. Called the 'C4 carbon-fixation pathway', this process is particularly efficient at high temperatures, in bright sunlight and under dry conditions[].

Edible Uses

Leaves - raw or cooked as a spinach[, , , ]. The leaves contain about 3.88% protein, 1.1% fat, 9.38% carbohydrate, 3.2% ash, 323mg Ca, 8.3mg Fe, they are very rich in Vitamins A & C, rich in vitamin B1[]. The leaves are used as a potherb in order to remove poison from the system[].

Seed - cooked. Used as a cereal substitute in cakes, porridge etc[, ]. Very small, about 1.2mm in diameter[], but it is easy to harvest and very nutritious. The seed can be cooked whole, and becomes very gelatinous like this, but it is rather difficult to crush all of the small seeds in the mouth and thus some of the seed will pass right through the digestive system without being assimilated[].
An edible dye is obtained from the seed capsules[].

Medicinal

A fluid extract of the plant is used as an astringent internally in the treatment of ulcerated mouths and throats, externally as a wash for ulcers and sores[].

The juice of the roots is used externally to relieve headaches[].

The plant has a folk reputation for being effective in the treatment of tumours and warts[].

Other Uses

Yellow and green dyes can be obtained from the whole plant[].

Propagation

Seed - sow late spring in situ. An earlier sowing can be made in a greenhouse and the plants put out after the last expected frosts. Germination is usually rapid and good if the soil is warm[], but poor germination rates are experienced in cool or cold soils[]. A drop in temperature overnight aids germination[].
Cuttings of growing plants root easily[].