Agaves

Of all the strange spiky botanical forms thriving in the Sonoran desert, some of the most spectacular and extravagant are the agaves. Flowering stalks of agaves begin to emerge as the weather warms in spring, and depending on the species, may grow to over twenty feet tall!   Their reproductive strategy is known colloquially as "boom and bust" reproduction, because the plant will live for many years as a leafy rosette, and then shoot up a stalk bearing hundreds or thousands of flowers in one season. The plant uses so much energy in the process that it dies after the seeds have ripened. The academic term for this is "monocarpic perennial," which translates to "a plant that lives for many years but only produces seeds once." Although agaves are sometimes called “century plants,” most species only live between 20-30 years.

Several years ago, I measured the daily growth of a few specimens in our neighborhood. My records show that agave flowering stalks will grow anywhere between 3 and 9 inches per day for one species I was tracking, Murphey’s Agave.  Murphey’s is one of several dozen types of agave found growing in the Phoenix area, thanks to a bustling import and cultivation business for use in ornamental landscaping. There are actually no wild agave populations within the metropolitan region, although several species grow naturally at higher elevations in surrounding mountains. However, there are a few small populations of Murphey’s, also known as Hohokam Agave, that appear to be remnants of pre-Columbian agricultural settlements. Agave has been, and continues to be, one of the most important utilitarian and food plants for indigenous cultures throughout the Sonoran desert.

Trade between ancient cultures played a large role in distributing agave to new areas far beyond their natural range. Many populations now known between central Arizona and Grand Canyon appear to be what is left of small plantations that were created to harvest for food, medicine and fiber. Both the piña and stalk of some species were roasted and eaten; the large stone-lined roasting pits remain as some of the most visible archaeological features of some pre-historic settlements.  The pulp and juice were also considered to be excellent tonics and healing medicine. Stalks were used as tools, building material and musical instruments. Fiber from the leaves was used to make sandals, fabric and nets. Be forewarned: the sap of some species is so toxic that it could be used as fish poison or arrow poison for hunting.  As noted by historian William H. Prescott in 1843: “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 civilization!”

Today, huge agave plantations are an important part of the North American economy. Tequila, mescal, agave syrup, and sisal are some of the major products exported from Mexico all around the world. Harvesting agaves is highly regarded as a technical skill, requiring strength and knowledge to recognize and properly cut the mature plants.  Harvesters, called jimadores, use specially designed cutting tools, called coas, to expertly remove the spine-tipped leaves and extract the piña, or core of the plant. Certain species are raised specifically for the fiber in leaves, which is used to produce everything from rope to place mats. Other species are best for the sweet sap that can either be pressed out and fermented to brew tequila, or reduced to make honey-like syrup. Industrial researchers are currently investigating the use of agave to produce bio-fuels. 

Despite the stunning effort put into seed production, very few of the tens of thousands of seeds made by a single agave actually germinate and grow into mature plants. For many species, most reproduction is from plantlets that emerge either on the stalk, called bulbils, or from the roots of the parent plant, called “pups” or hijos (Spanish for “sons”).  These smaller plants are the form that has been most easily traded for thousands of years, and allows us to now enjoy so many kinds of agaves in the suburbs of Phoenix.  Part of the job of an jimadore on an agave plantation is to extract the parent plant without destroying the hijos. Likewise, if you have the privilege of witnessing the flowering and passing of an agave in your home landscape, be sure to collect the hijos and find a good home for them to carry on their line of noble plants.