Agave Growth and Harvesting
04. Anatomy & Reproduction
Agave Anatomy
Agave tequilana has a set of characteristics that are unique to the variety. The color, as is indicated in the name, is a light grey-blue. The plants grow best in direct sunlight and can survive in a multitude of environmental circumstances, from subtropical to semi-arid and sub-humid conditions.
Plants grow approximately 47 – 70 inches (120 – 180 cm) high and leaves extend 35 – 47 inches (90 – 120 cm) long, growing in the shape of a spear head and formed with very solid fibers that make them rigid and strong. The leaves grow in a way that fashions a rosetta, allowing the lower leaves to receive sunlight.
Each agave typically grows around 130 leaves in a 7‑year growth period, some of which can reach up to 5 feet long. When leaves die, they descend to the ground, covering the topsoil to lock humidity in the soil.
The trunk, heart, or piña (i.e., the central core of the plant) resembles a pineapple, circular in shape and thick with a height of 11 – 19 inches (30 to 50 cm). Its average weight is approximately 66 pounds (30 kg) after 6 years of growth.
The total biomass of agave is approximately 50% piña and 50% leaves, and we can roughly divide the content of agave into three elements based on its weight: Water: 70%, Fiber: 5% and Carbohydrates (inulin): 25%.
credit: Chloe Harrison-Ach
Reproduction
The piña is the inulin reserve of the agave (inulin is a naturally occurring polysaccharide used by some plants as a way of storing energy), which facilitates the production of the quiote when the plant is mature.
The other way Weber Blue agaves reproduce asexually is through little baby plants called hijuelos that grow around the bases of the mother plant. These offshoots start growing organically at ground level, joined to the mother plant through a rhizome (commonly known as chirrion), when the plant reaches about 3 – 6 years old. Agaveros harvest the “pups” when they reach one year old, i.e., strong enough to be transplanted. After about 6 years the plant produces hijuelos that are too weak to survive and these are often discarded. The use of hijuelos to replant in a new field is the most common way to reproduce agave for tequila production.
The quiote grows out of the center of the plant, like a very large, thick asparagus stalk, which then produces bulbils and flowers. Bulbils are like small hijuelos, or offshoots, produced on the branches of the quiote, that require a long period of time to grow if sown for the purpose of starting a new agave plant.) The flowering and pollination of the agave’s flowers is one way the plant reproduces sexually, as bees, hummingbirds and bats transport the seeds to new locations. The germination percentage of seeds is low and the development of new plants is very slow, so like bulbils, this method is not often used in tequila production. Each plant is monocarpic, that is, it flowers once during its lifetime (at about 10 years old), then withers and dies.
credit: Chloe Harrison-Ach
MANITAS — (Umbel) flowering begins with an inflorescence of short flower stalks which spread from a common point (like umbrella ribs).
credit: Chloe Harrison-Ach
CAYACAS — (Flower buds) grow at the ends of the manitas after the quiote reaches full height.
credit: Chloe Harrison-Ach
FLORA — (Flower) fully opened flowers open from the cayacas, attracting local pollinators and allowing the agave the chance toreproduce sexually.
credit: Chloe Harrison-Ach
PLATANITOS — (Capsule) the flora eventually dry into a seed capsule. Some capsules have wings allowing them to be carried by the wind, but most fall around the plant.
It was for many years assumed that the Weber Blue agave’s reproduction via hijuelos produced an exact clone of the mother plant, which contributed to monoculture of large crops that are genetically identical to each other. Recent scientific research shows that the Weber Blue agave has a mechanism that generates a change in the genetic profile of the new plants with regards to the mother plant in the three ways of reproduction. While plants that are grown from pollinated seeds may have the most genetic diversity from their mother plant, there is still genetic diversity between plants grown from hijuelos (most common) and bulbils, and their mother plant. This emerging research is promising for the future diversity and sustainability of agave agriculture.