Common Name: Spleen Amaranth

General Information

Amaranthus dubius is a vigorous, erect, annual plant with a branched stem, growing from 30 - 150cm tall[, ].
The plant is harvested from the wild for local use as a food. It has a long history of cultivation, especially for its leaves. It is still sometimes grown, especially in the tropics, as a leaf crop.
A prolific producer of seed, the plant has often escaped from cultivation and become a weed of cultivated and disturbed ground outside its native range[].

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

S. America - Brazil, Peru, Ecuador, Colombia, Venezuela, the Guyanas; C. America - Panama to Mexico; Caribbean - West Indies.

Habitat

Naturalised in Florida where it grows in waste places and disturbed habitats at elevations of 0 - 100 metres[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	1.00 m
Pollinators	Wind, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

A plant of the tropics, it has long been cultivated outside its natural range, succeeding from the temperate zone to most areas of the tropics, at elevations up to 1,200 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 30°c, but can tolerate 12 - 45°c[]. It can be killed by temperatures of 4°c or lower[]. It prefers a mean annual rainfall in the range 2,100 - 2,400mm, but tolerates 700 - 4,000mm[].
Prefers a well-drained fertile soil in a sunny position[], though it can tolerate a wide range of conditions[]. Requires a hot sheltered position if it is to do well[]. Prefers a pH in the range 6 - 7.5, tolerating 5.5 - 8.5[].
Plants can bear their first crop of edible leaves within 30 - 50 days from sowing the seed[]. If the plant is cut back and not uprooted, it may continue to produce further crops of leaves for 120 - 300 days[].
This species most probably originated as a result of ancient hybridization between A. Spinosus and either A. Hybridus or A. Quitensis[]
The plant is sometimes cultivated in tropical areas for its edible leaves, there are some named varieties. The cultivar 'Claroen' is considered to be one of the best cultivars[].
Plants are particularly susceptible to attacks by leaf-chewing insects[].
Plants should not be given inorganic fertilizers, see notes above on toxicity.
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 - cooked[, ]. Used as a potherb, they are considered to be very palatable[]. A mild flavour, they are sometimes cooked with more bitter-flavoured leaves[]. The leaves quickly become soft within 5 - 10 minutes of cooking[].

Seed - cooked[]. Rather small, but very nutritious, it can be ground and used as a powder. 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[].

Medicinal

Amaranth leaves in general are recommended as a good food with medicinal properties for young children, lactating mothers and for patients with fever, haemorrhage, anaemia, constipation or kidney complaints[].

The whole plant is used as a medicine against stomach ache[].

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[].