Purple Amaranth, Red amaranth

Amaranthus cruentus

Physical Characteristics

Amaranthus cruentus is a ANNUAL growing to 2 m (6ft 7in). See above for USDA hardiness. It is hardy to UK zone 4 and is frost tender. It is in flower from July to September, and the seeds ripen from August to September. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Wind. The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It cannot grow in the shade. It prefers moist soil.

Distribution

Original habitat is obscure, it was probably tropical America.

Habitats

Cultivated Beds;

Edible Uses

Edible Parts: Leaves Seed Edible Uses: Colouring Amaranthus cruentus has a long history of cultivation, especially in South and Central America, where it was grown as a staple seed crop by the Aztec and Maya civilizations. It remains a traditional and important crop in Mexico, Guatemala, and the Andes. Unlike Amaranthus blitoides or A. albus, red amaranth is primarily a cultivated species rather than a common wild plant, and thus less likely to be encountered by casual foragers [2-3]. The seeds are highly nutritious and versatile, ranking among the best of all amaranths. They can be popped like popcorn, toasted, boiled into porridge, or ground into flour for breads and cakes. Seeds are usually lighter-colored than those of wild amaranths, often cream to golden, and are much easier to process. Their protein content is complete, rich in lysine, which is rare for grains [2-3]. The leaves are also edible, though they are less commonly used than the seeds. They can be eaten fresh, cooked, or boiled, with a flavor similar to spinach but often milder [2-3]. Culturally, A. cruentus was used by the Hopi people of Arizona to color traditional “piki bread.” The deep red flower spikes imparted a pink hue to this iconic ceremonial food [2-3]. Edibility Rating: 5/5 – Excellent seed crop, with additional value in leaves.Leaves - cooked as spinach[183]. The mild-flavoured leaves are rich in vitamins and minerals[183]. Seed - very small but easy to harvest and very nutritious. They are eaten cooked or ground into a powder and used for making cakes etc[183, 257]. They can also be sprouted and used in salads[183]. 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[K]. The flowers are used as a food colouring in ceremonial maize bread[183].

Medicinal Uses

The plant can be cultivated from the tropics to the temperate zone. It grows best in areas where annual daytime temperatures are within the range 22 - 28°c, but can tolerate 10 - 45°c[418 ]. It can be killed by temperatures of 4°c or lower[418 ]. It prefers a mean annual rainfall in the range 2,000 - 2,400mm, but tolerates 500 - 4,000mm[418 ]. Prefers a well-drained fertile soil in a sunny position[200 ]. Requires a hot sheltered position if it is to do well[K ]. Prefers a pH in the range 5.5 - 7, tolerating 4.3 - 7.5[418 ]. Often cultivated as a food crop and ornamental plant, it has escaped from cultivation in many areas and become naturalised as a weed of cultivated and disturbed ground[305 ]. A fast-growing plant, the first crop of leaves can be harvested in 30 - 50 days from sowing the seed, and the plant can carry on being harvested for up to another 250 days[418 ]. Grain yields usually range from 800-1200 kg/ha but with the use of fertilizers the yield can be raised up to 3 t/ha. This species is cultivated for its edible seed in many parts of S. America and in Japan[58 , 97 , 183 ]. There is at least one named variety, 'Oeschberg' is a very productive plant, growing 1 metre tall and can yield up to 2.5 tonnes per hectare[183 ]. This species is the most adaptable of the grain amaranths, it also flowers under a wider range of daylength hours than the other species[183 ]. Plants are particularly susceptible to attacks by leaf-chewing insects[298 ]. 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[196 ].

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.