Agave is a genus of monocots. The plants are perennial, but each rosette flowers once and then dies. Some species are known by the name century plant. The name "century plant" refers to the long time the plant takes to flower.
A number of by products are produced from agave plants: Agave nectar (also called agave syrup) used as a sugar alternative. The flower sap is distilled and used to produce the sprit: mezcal. Tequila is the best known version of this spirit. Paper and writing materials can be manufactured from the leaves and thorns. The leaves and flower heads can be boiled and roasted as vegetables, though as it only flowers once ever hundred years, it can hardly have been a common food!
One of the most familiar species is Agave americana, a native of tropical America. Common names include century plant, maguey (in Mexico), or American aloe (it is not, however, closely related to the genus Aloe). The number of years before flowering occurs depends on the vigor of the individual plant, the richness of the soil, and the climate; during these years the plant is storing in its fleshy leaves the nourishment required for the effort of flowering.
Chiefly Mexican, agaves are also native to the southern and western United States and central and tropical South America. They are succulents with a large rosette of thick, fleshy leaves, each ending generally in a sharp point and with a spiny margin; the stout stem is usually short, the leaves apparently springing from the root. Along with plants from the related genus Yucca, various Agave species are popular ornamental plants.
Each rosette is monocarpic and grows slowly to flower only once. During flowering, a tall stem or "mast" grows from the center of the leaf rosette and bears a large number of short, tubular flowers. After development of fruit, the original plant dies, but suckers are frequently produced from the base of the stem, which become new plants.
It is a common misconception that agaves are cacti. They are not related to cacti, nor are they closely related to Aloe whose leaves are similar in appearance.
The ethnobotany of the agave was eloquently described by William H. Prescott in 1843:
But the miracle of nature was the great Mexican aloe, or maguey, whose clustering pyramids of flowers, towering above their dark coronals of leaves, were seen sprinkled over many a broad acre of the table-land. As we have already noticed its bruised leaves afforded a paste from which paper was manufactured, its juice was fermented into an intoxicating beverage, pulque, of which the natives, to this day, are extremely fond; its leaves further supplied an impenetrable thatch for the more humble dwellings; thread, of which coarse stuffs were made, and strong cords, were drawn from its tough and twisted fibers; pins and needles were made from the thorns at the extremity of its leaves; and the root, when properly cooked, was converted into a palatable and nutritious food. The agave, in short, was meat, drink, clothing, and writing materials for the Aztec! Surely, never did Nature enclose in so compact a form so many of the elements of human comfort and civilisation!
There are four major parts of the agave that are edible: the flowers, the leaves, the stalks or basal rosettes, and the sap (in Spanish: aguamiel, meaning "honey water").
Each agave plant will produce several pounds of edible flowers during its final season. The stalks, which are ready during the summer, before the blossom, weigh several pounds each. Roasted, they are sweet and can be chewed to extract the aguamiel, like sugarcane. When dried out, the stalks can be used to make didgeridoos. The leaves may be collected in winter and spring, when the plants are rich in sap, for eating. The leaves of several species also yield fiber: for instance, Agave rigida var. sisalana, sisal hemp, Agave decipiens, false sisal hemp. Agave americana is the source of pita fiber, and is used as a fiber plant in Mexico, the West Indies and southern Europe. During the development of the inflorescence, sap rushes to the base of the young flower stalk. Agave nectar (also called agave syrup), a sweetener derived from the sap, is used as an alternative to sugar in cooking, and can be added to breakfast cereals as a binding agent. The sap of A. americana and other species is used in Mexico and Mesoamerica to produce pulque, an alcoholic beverage. The flower shoot is cut out and the sap collected and subsequently fermented. By distillation, a spirit called mezcal is prepared; one of the best known forms of mezcal is tequila. In 2001, the Mexican Government and European Union agreed upon the classification of tequila and its categories. All 100% blue agave tequila must be made from the Weber blue agave plant, to rigorous specifications and only in certain Mexican states.
When dried and cut in slices, the flowering stem forms natural razor strops, and the expressed juice of the leaves will lather in water like soap. The natives of Mexico used the agave to make pens, nails, and needles, as well as string to sew and make weavings. Leaf tea or tincture taken orally is used to treat constipation and excess gas. It is also used as a diuretic. Root tea or tincture is taken orally to treat arthritic joints. Several agave species are also considered to have potential as effective bioenergy crops. Agave's ability to grow in naturally water-limited environments could help to reduce the food vs fuel trade-off. The agave, especially Agave murpheyi, was a major food source for the prehistoric indigenous people of the Southwestern United States. The Hohokam of southern Arizona cultivated large areas of agave. The Navajo similarly found many uses for the agave plant. A beverage is squeezed from the baked fibers, and the heads can be baked or boiled, pounded into flat sheets, sun dried, and stored for future use. The baked, dried heads are also boiled and made into an edible paste, eaten whole, or made into soup. The leaves are eaten boiled, and the young, tender flowering stalks and shoots are roasted and eaten as well. The fibers are used to make rope, the leaves are used to line baking pits, and the sharp pointed leaf tips are used to make basketry awls.