pierre laszlo

Amaranthus caudatus (Amaranthaceae).

Plant of the month    (©Pierre Laszlo, all rights reserved)

Amaranth is a rather archaic name for a color, a deep, velvety purple. Not the name of a plant, then? Yes, of course: the color is named after the flowers. These are extremely showy, a cascade with drops of deep, velvety purple, ‟brilliantly colored plumes of deep red with green and salmon-pink nuances,‟ in one of the descriptions.
In addition to its scientific name, the plant is commonly known as pigweed, purple amaranth, love-lies-bleeding, tassel flower and — my favorite, in direct translation from the French — amaranth fox-tail, referring again to the opulent, extremely colorful inflorescence.
The red dye from the broad leaves colors alcoholic beverages in Bolivia and northwestern Argentina, maize dough in Mexico and the southwestern United States. It also dyes foods and beverages in Ecuador.
The stem is long, it can reach 2 m. Leaf blades are 2-20 cm in length. The inflorescences are axillary or terminal. If the latter, they consist usually of a panicle with numerous clusters of short to long, dense spikes, the cascading flowers mostly continuous along the spikes. The flowers have five sepals, the same number of stamens, the fruit is a couple of mm long, the seeds to which we shall return are tiny, about 1 mm in diameter.
Inside a seed, the embryo surrounds the starchy tissue, whereas in the grain of a cereal, the embryo is embedded in the starchy tissue. Thus amaranth is known as a pseudo-cereal. 
Seed yield reaches up to 3 t/hectare when grown in monoculture for 3-4 months, and a vegetable yield of 4.5 tons dry matter/hectare after 4 weeks. It works well in rotation with corn and soybeans. The crude protein content of grain amaranth ranges from 12.5 to 17.6 % dry matter. This is higher than in most common grains except soybeans. It is very healthy, the amino acid composition of amaranth protein meets the American FAD/WHO protein standard . Also, it is gluten-free, a plus to those with nutritional allergies. The total lipid content of grain amaranth ranges from 5.4 to 17.0% dry matter, with high level of unsaturation (about 75%), containing almost 50 % linoleic acid.
The harvested amaranth plant is 50-80 % edible. By contrast, only 20-30% of most vegetable plants are currently consumed by Americans.
Why did amaranth not accompany potatoes, tomatoes, and the other plants of Meso-American origin that first entered European and later worldwide cultivation? It is one of the vagaries of history. One can speculate on the reasons. True, machines do not take kindly to the tiny seeds of amaranth. However, modern technology easily copes with that sort of issue. Maybe also, the gorgeous flowers limited the plant to a niche, for its decorative value? With a wide tolerance of different soils and climates, amaranth could be grown in many parts of the world.
Amaranth flour, at about 20 %, has been successfully utilized as a supplement for corn flour in tortillas and wheat flour in bread. There is currently an attempt at reviving amaranth production. In recent years, another long-forgotten plant, quinoa, from the same region of the Andes, has achieved the status of a ‟novel‟ grain, first in luxury restaurants, later on with the health-food industry and now has trickled down to the middle-class. No doubt, amaranth growers wish emulating the quinoa success story. 
Hunter-gatherers ate amaranth in both North and South America before the advent of agriculture. It is one of the oldest known food crops: domestication occurred independently in the Andes and in Mexico. In Mexico, it occurred about 5000 BCE, together with beans, maize, gourds. A close relative, Amaranthus cruentus, was found in Tehuacán, Puebla, Mexico, about 4000 BCE. Another close relative, Amaranthus hypochondriacus — the genus Amaranthus has at least 60 species — is native to the Tehuacán Valley, where it was domesticated between 5200 and 3400 BCE.
In Pre-Hispanic times, Amerindians cultivated the plant. It was known as kiwicha. Together with maize and quinoa, it was one of their main crops. They ate the leaves as a vegetable while the seeds served as a cereal. They can be ground into a flour, popped like popcorn or flaked like oatmeal.
Quechua Indians — who gave the potato plant to the world — still grow amaranth in Andean valleys of Peru, between 2700 and 3500 m elevation. This subsistence cultivation — the yield in the highlands is about half of what it is at lower elevations — probably has little changed since pre-Columbian times. Amaranth is grown intercropping with maize as the main crop. Indians sow kiwicha in rows 30 cm-1 m wide, paralleling rows of maize at regular intervals of 2-3 m. Alternatively, sown amaranth makes up part or the whole perimeter of a maize field. 
The Aztecs grew amaranth using chinampa agriculture. At the time of the Spanish contact, shallow lakes covered approximately 1000 km2 of the Basin of Mexico. Large expanses of the swamps were drained and converted into chinampas. These are rectangular fields 2 to 4 m wide and 20 to 40 m long, surrounded on three or four sides by canals. Chinampa farmers pile layers of vegetation and mud or dirt to raise the field surface to about 1 m above the water level. It allowed a most productive form of intensive agriculture, to the extent that chinampas provided one-half to two-thirds of the food consumed in Tenochtitlan, the capital of the Aztec Empire, whose population, at the time of the Spanish contact numbered between 150,000 and 200,000.
Montezuma II, at the time of the Conquest, received tribute from farmers in 17 provinces. This filled 18 Imperial Granaries each year, a single granary held of the order of 10,000 bushels of grain. 
The Spanish however outlawed the growing of amaranth. Amaranth dough played a key role in an important religious ceremony of the Aztecs — who assimilated amaranth with their god Huitzilopochtli — and thus would interfere with the intended spread of Christianity.