Common Name: Spiny Amaranth

General Information

Amaranthus spinosus is an erect, much-branched annual plant growing up to 100cm tall[].
The plant is harvested from the wild for local use as a source of food and medicines. The leaves are occasionally sold as a vegetable in local markets[, ].
The plant produces seed prolifically, with almost 250,000 seeds being recorded from one plant. It has spread as a weed of disturbed ground from its original range in the Americas to many other areas of the world[]. When the world's worst weeds are ranked on the basis of the number of pests hosted, Amaranthus spinosus is placed number 6, hosting 15 pests that may affect crops[].

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 pantropical weed, extending sometimes into the temperate zone, it originally came from Tropical America.

Habitat

Roadsides, waste places and fields in South-eastern N. America[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	0.60 m
Pollinators	Wind, Self
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Prefers a well-drained fertile soil in a sunny position[]. Grows best in a moist soil, but is able to tolerate fairly dry soils and also quite wet, but not waterlogged, ones[, ].
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 and stems - raw or cooked as a spinach[, , ]. If older leaves and stems are used the spines must be removed[]. Highly esteemed[]. A bitter flavour, it is usually only eaten in small quantities as a substitute when no other vegetables are available[]. The dried leaves contain (per 100g) 267 - 276 calories, 20 - 34.4% protein, 2 - 4.5% fat, 45 - 54% carbohydrate, 9.8 - 10.4% fibre, 16.6 - 24% ash, 1795 - 5333mg calcium, 333 - 460mg phosphorus, 13.5 - 152.7mg iron, 13 - 37mg sodium, 337 - 3528mg potassium, 27.9 - 40.8mg beta-carotene equivalent, 0.06mg thiamine, 2.02mg riboflavin, 7.7 - 8.6mg niacin and 503mg ascorbic acid[].

Seed - cooked. Very small, about 1mm in diameter[], but 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[].

The ash of the burnt plant is used as a salt[]. It is also added to the water as a tenderizer when cooking tough vegetables such as cowpea leaves and pigeon peas[].

Medicinal

The seed is used as a poultice for broken bones[].

The plant is astringent, diaphoretic, diuretic, emollient, febrifuge and galactagogue[, , , , , , ]. It is used internally in the treatment of internal bleeding, diarrhoea and excessive menstruation[, ]. It is also used in the treatment of snake bites[].
Applied externally, it is used to treat ulcerated mouths, vaginal discharges, nosebleeds and a range of skin problems including wounds, eczema, boils and burns[, , ]. The plant can be used fresh or it can also be harvested when coming into flower and dried for later use[]. The ash of the plant, combined with water, is used to wash sores[].

The sap is used as an eye wash to treat ophthalmia and convulsions in children[].

The root is diuretic, emmenagogue, febrifuge and galactagogue[, ]. The juice of the root is used in Nepal to treat fevers, urinary troubles, diarrhoea and dysentery[]. It is also used, often combined with the root juice of Dichrophela integra and Rubus ellipticus, to treat stomach disorders and, on its own, to treat indigestion and vomiting that occur after eating unusual foods[].
A paste of the root is used in the treatment of menorrhagia, gonorrhoea, eczema and colic[, ]. It helps to remove pus from boils[]. It is used to treat toothache[].

Other Uses

The seed contains up to 17% oil[]. This oil is a relatively good source of squalene (2.4 to 8.0%) and is a relatively high value lipid. Squalene is an expensive terpenoid compound, derived primarily from shark and whale liver oils. It has many applications in the pharmaceutical and cosmetic industries, as an ingredient in cosmetics; for skin penetrants; and as lubricants for computer disks, for example[].

Yellow and green dyes can be obtained from the whole plant[].
A red pigment obtained from the plant (the report does not specify which part of the plant) is used as a colouring in foods and medicines[].

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[].