Agave Trincheras
Welcoming visitors to Mission Garden, along the slope just east of the walkway towards the main entrance, are a series of agave terraces known as trincheras. They are designed to emulate those of the ancient Hohokam farmers of this region who planted agaves in rock alignments, or piles, set in drainages on rocky slopes to capture rainwater runoff, thus taking advantage of otherwise nonarable land for food production.
Agaves were a major source of food and fiber for local desert-dwellers, who cultivated extensive fields of them throughout Aridamerica. People began to select certain plants for desirable traits, such as the sweetness of the hearts when roasted, ease of propagation, shorter times to harvest, and less caustic leaves. This led to the development of several semi-domesticate, or anthropogenic, species of agave, some of whose relic populations still exist in “the wild”, often associated with archaeological sites, in our region.
Interpretation of Hohokam agave culture by artist Miguel Molina. Agaves served as tasty, nutritious and easily stored food, as well as for fiber used to make cloth, rope, sandals, baskets and brushes. The leaves were also used as building materials. When left to bloom, the flowers serve as an important food source for pollinators, including bats.
Archaeologists working in this area, foremost among them Suzanne and Paul Fish, have discovered numerous ancient agave roasting pits, rock-piles, contour terraces, checkdams, stone agave processing tools, and agave quids (balls of chewed fibers). These are all keys to understanding the significance of agave as a keystone species for food and fiber between the slopes of the Tortolita and Tucson Mountains. Most of the agave plants in our trincheras at Mission Garden are Agave Murpheyi, known as Hohokam Agave because it has been found to be associated with Hohokam archaeological sites, such those in Tumamoc and Marana. Remnant populations of these anthropogenic species of agave existing in the wild are increasingly rare and endangered. Some of the other semi-domesticate species remaining in Arizona that have been identified by agave expert Wendy Hodgson include Agave chrysantha, A. palmeri, A. delamateri, A. phillipsiana, A. verdensis and A. yavapaiensis. Growing and preserving these species that are believed to have been cultivated by ancient farmers in the region connects us directly to our local farming heritage and enables us to benefit from the process of domestication achieved over millennia.
At Mission Garden we aim to continue creating more and more trincheras, and planting more and more agave all around the Garden so that we may eventually have several agave that are sending up their stalks to bloom every year. This way, we will be able to harvest some of them to roast in our roasting pit, in keeping with our mission to preserve local food traditions, while also allowing some to bloom and provide sustenance for the many pollinators, including bats, who rely on them.
Starting in 2016, several volunteer crews began helping us build these trincheras and plant agave. It has been a great way to learn hands-on about ancient agricultural practices and water harvesting methods, keys to growing food in our desert, especially with climate change upon us. Pictured here, Salpointe High School students participated in the first planting of agave, with the guidance of former gardener José Gastellum.
These trincheras exemplify how Mission Garden is undertaking a process of the environmental restoration of degraded land, in this case quite literally turning garbage into gardens. The trincheras are planted at the edge of the former City dump, atop the landfill cap. During the early years of the Garden, the soil covering the old dump was eroding, and Tucson’s old garbage was increasingly exposed. Environmental Services denied us permission to dig and plant trees or shrubs to counter the erosion.
Fortunately, archaeologist Suzie Fish suggested we place rocks where runoff was forming rivulets in the landfill cap, bring in soil to add behind the miniature retaining walls formed by the rocks, and plant small agaves. By following her sage advice we have been able to avoid digging into the landfill, while succeeding in countering the erosion, beautifying the entryway, and interpreting ancient agricultural and water-harvesting techniques, all in one fell swoop.
Agave murpheyi, known as Hohokam agave, planted atop the landfill cap of the former city dump, just east of the garden
