In this article I’d like to cover permaculture food forest theory for the Sonoran Desert. In future posts, we will discuss the basics of passive solar design, permaculture design principles, and how to plant the rain. The term permaculture comes from coupling the words permanent and agriculture. It’s a design philosophy that’s cross-disciplinary and includes agriculture, architecture, biology, ecology, economics, and community design. The basic idea behind permaculture is to create regenerative systems that provide for their own needs and recycle their waste.
I want to start a conversation about permaculture theory and how it applies to us in the Sonoran Desert. I want this to be a resource for the entire community. Not everyone can afford to attend a permaculture design course, and this reality shouldn’t preclude people from accessing and learning about permaculture, because it should be for everyone. This lack of access has created a misunderstanding about what permaculture actually is. To those on the periphery, it’s just another gardening method, one choice in a plethora of gardening methods. This point of view misses the fact that permaculture is a revolutionary lifestyle. For example, when most backyard growers start a hot compost pile they use manure from livestock, often going through great pains to truck in manure for composting purposes. When permaculturists start a hot compost pile, we use our own manure. Our humanure amends garden beds that grow vegetables and fruits. We then eat that food! Composting your own feces, growing food with it, and, finally, eating that food, is a revolutionary act of the first degree. Permaculture is about the land and how we use it. As a revolutionary movement and lifestyle that radically roots us in nature, it reconnects us with the natural world and allows us to become one with that world. An underlying goal of the permaculture movement is to shift how we, as human beings, interact with the natural ecosystems we inhabit.
Permaculturists often look to the natural structure of a living forest to glean lessons. This is our learning lab. By studying how a forest regenerates itself, we can mimic the underlying system that creates the conditions in which life thrives. For example, what are the underlying mechanisms that a forest uses to spread itself? Birds are key players in spreading seeds, and through their natural behavior are full time planters of edible shrubs, bushes, and trees. The inverse is also true. For example, if we let livestock, who are being fed invasive weeds, graze public lands, then they, too, are full time planters, but of species that weaken the regenerative mechanisms of the ecosystem. Human beings, because of our unique ability to create technology, can greatly enhance or destroy the natural regenerative patterns of a local ecosystem. How we practice agriculture in the Sonoran Desert matters. We must first, however, understand how the Sonoran Desert regenerates itself. I’m going to cover the basic mechanisms, that forests use to create themselves, so we’re all on the same page with these natural patterns of the forest. I will try to answer the following question: What does a native plant based Sonoran Desert food forest look like?
The concept of a food forest can be broken up into seven categories that work together to create a self-generating system:
Now, it’s important to understand that this is site-specific. For example, if we’re in a Sonoran Desert riparian area where native cottonwoods are naturally growing, then cottonwoods would constitute our tall tree layer. However, if we’re in the urban core, where cottonwoods do not grow naturally, then mesquite, palo verde, or ironwood trees would become our tall tree layer. These are nuances we need to keep in mind when designing a food forest in the Sonoran Desert. Food Forest theory is specific to place and the surrounding ecosystem of which it is a part. We are looking for the seven layers within the niche, or micro-climate, that we’re actually working with. Let’s get deeper into these seven categories, explore how we can apply them to the Sonoran Desert, and talk permaculture theory along the way.
The tall tree layer is crucial to establishing a regenerative system because it provides the form to the function and should be the primary focus when establishing a new permaculture site. It’s important to remember that we’re in the desert and we lack water. For this reason, all of our plantings should be done in rainwater harvesting earthworks. By utilizing passive rainwater harvesting methods and techniques, we can create a strong resilient food forest system. In future blog posts, I will cover the how of water harvesting, but for now we’ll focus more on the why. Can I install a drip irrigation system and plant exotics like roses and fruit trees? Yes, I can totally do that, but can this system handle future water restrictions? How about an irrigation system failure when I’m out of town on vacation? How much time do I want to invest in covering exotic plants from our hard freezes in the winter? At the heart of permaculture theory is the idea of establishing regenerative systems. A system that can re-create itself without our input. The more we have to intervene in our system (i.e. cover up plants, rely on the municipal water supply, etc.) the less resilient our system is in times of crisis. Our system is most likely to fail if we don’t have a regenerative foundation that we’re building on. Establishing keystone species like the tall tree layer will create the conditions that our annual garden beds need to thrive. Their shady canopy is where I can plant chiltipin bushes and medicinal herbs. Planting a tall tree layer also encourages us to re-landscape our property on contour. By slowing, spreading, and sinking rainwater throughout the landscape, we are tapping into the natural patterns of the Sonoran Desert. Well-mulched rainwater harvesting earthworks, with food bearing native trees, is the foundation for growing abundance in this harsh and extreme climate.
The Sonoran Desert has three native edible trees that can survive solely on our rainfall once they’re established: mesquite, palo verde, and ironwood trees. Think about that for a second. You can grow trees that will produce a tangible and usable bumper crop on our minimal rainfall. All are legumes, which means they will fix nitrogen into the soil via natural leaf and seed drop. They all produce edible beans while at the same time enriching the soil. Mesquite pods can be ground into flour with a hand mill or hammer mill. Mesquite flour is a sweet, low glycemic flour that can be used to make pancakes, tortillas, bread, or anything else in which we would use wheat flour. Palo Verde beans can be eaten raw like snap peas when young, as sprouts when mature, or ground into flour using a hand mill or hammer mill after they have been dried. Ironwood seeds, which are good sprouted, are often referred to as desert peanuts because they have a similar flavor.
These three edible trees can grow to be 25-30 feet tall and can thrive solely on rainfall while producing a bumper crop in your yard. Mesquite and Palo Verde trees are semi-deciduous, meaning that in a mild winter they will not lose their leaves. They are extremely hardy trees. Although, ironwoods are evergreen and don’t lose their leaves in the winter, they are sensitive to freezing temperatures. Their natural habitat is southeast or southwest facing mountain sides in the Sonoran Desert, where they receive good sun exposure in the winter season. The mature canopy of these trees can house other perennial and annual layers of the food forest that require filtered sunlight in order to thrive.
Now, let’s talk about the low tree layer and native edibles. This is where things can get confusing, as most of the plants that would fit in this category are not trees at all. We’re going to include food bearing bushes in this category: mid-story plants that are no taller than 15ft. My personal favorite is the Mexican elderberry, which reaches a height of 13 feet when mature. It produces medicinal flowers and berries in the spring and is a medium water use plant, which means it needs to be in a prime rainwater harvesting earthwork, or even a greywater basin. Mexican elderberries can survive on rainfall alone. However, they may not flower and produce berries in abundance with minimal water. Folks in the urban core are surrounded by hard impervious surface areas like asphalt and concrete. We can take advantage of their impenetrability by redirecting rainfall into earthworks in order to sustain a thriving Mexican elderberry tree. Most people know about goji berries, but do not realize that we have a native relative of the goji berry: the wolfberry bush. Reaching heights of 10-13 feet when mature, the wolfberry is also a medium water use plant. We can also use a desert hackberry bush (not to be confused with the hackberry tree), which produces delicious berries, but again this is a medium water use plant. Now, these are all great choices for food bearing plants for humans. If we want to plant something for wildlife, then we can look to the Acacia family, which average 15 feet tall and produce seeds that wildlife love.
This brings us to the shrub layer, where the Sonoran Desert really shines with options. We have over 540 edible or medicinal plants to choose from, and most of them happen to fall into the shrub and herbaceous layer. Think of prickly pear, prickly pear fruit, barrel cactus fruit, and cholla buds. These relatively hardy plants are standard native edibles that can thrive in a variety of conditions. Peppering earthworks with tall, mid, and low -story plants creates an ideal habitat for native wildlife. With a proper hunting license, abundant wildlife can become a surplus of our permaculture system. For example, let’s say you don’t like eating cholla buds, prickly pear pad, or prickly pear fruit. Plant them anyway, because they will entice rabbits, squirrels, and birds that we can harvest instead. Permaculture is about establishing a food forest that benefits everyone, including wildlife.
The herbaceous layer leans heavy with medicinal plants in the Sonoran Desert. Some of these can double as edibles like desert mallow, chia, lambsquarters, wild amaranth, devil’s claw, mustard greens, and dandelions. In my experience, these naturally show up after a site has installed earthworks and is well mulched. The birds and wildlife will bring these in for you. Some of the more medicinal plants are datura, prickly poppy, crowns beard, globemallow, desert tobacco, and Mexican golden poppy. The herbaceous layer is key for attracting pollinators and convincing them to stay for a while, because most of these plants flower and produce pollen.
The ground cover layer consists of plants like ground cherries (wild tomatillos), purslane, Mexican oregano, and deer weed. There aren’t a ton of native edible ground covers, but there are a lot of medicinal ground covers. Remember that it’s about diversity in the canopy structure. We want a good tall, mid, and low story structure in our landscape. This will bring in the wildlife, which means free native seed bombs in the form of their manure droppings. In many ways our rainwater harvesting earthworks will be doing a lot of the legwork by creating habitat for native wildlife. They are co-creators in our permaculture system.
Now for the root layer. We can use wereke, cholla, desert rhubarb, and yucca root for medicinal applications. In other forests with more water we could literally plant potatoes, carrots, and other root crops as part of our system, but this is not our reality in the Sonoran Desert. Desert rhubarb and wereke produce sizeable tubers, but have a relatively high water demand. In the Sonoran Desert these tubers only grow in certain spots and require skill to grow in the urban core. We have to recreate their natural conditions. These tubers are not edible. We can, however, make a very strong medicine with the roots. Desert rhubarb can heal mouth sores. Wereke is used for diabetics in Mexico. The roots of a cholla can be made into a tea for kidney related issues. We can use the saponin content of the yucca root to brew up fungal-dominated compost tea, or ferment it to make our own wetting agent for gardening purposes.
Now the vines! Did you know that we have a canyon grape? It is a native wild grape that can be propagated by cutting or seed. It’s definitely in Southern Arizona and produces very small grapes and leaves that are edible. Some folks even make wine out of these tiny grapes. The other edible vine we have is the Tumamoc globeberry, which produces a watermelon-like fruit. We have many hummingbird and butterfly vines that thrive on rainwater, too. Wereke is also a vining, flowering, and fruiting tuber.
For the sake of walking you through basic permaculture food forest theory, I’ve focused mainly on medicinal and edible plants that are native to the Sonoran Desert. We could add other beneficial native plants that are good for pollinators, nitrogen fixers, building materials, tool making, or supporting wildlife. We live in a unique desert. We are surrounded by resilient edible and medicinal plants that are underutilized, underestimated, and undervalued. We need to challenge what our concept of food is. I can grow more usable grain with rainwater by planting mesquite trees than I can growing wheat with tap water. A mature mesquite tree uses approximately 3,000 gallons of rainwater per year and will produce pounds of gourmet flour. A ten-foot prickly pear hedge can easily fill several five gallon buckets full of ripe fruit. Don’t forget that we have berries! Dehydrated wolfberries are so good. Elderberry syrup in the winter season is a must have. Chiltipin are native to the Sonoran Desert and grow wild here. One little chiltipin pepper has more vitamin C than a whole orange. A pound of chiltipin can go for fifty dollars, mesquite flour goes for twenty dollars a pound, cholla buds go for twelve dollars for four ounces! We are over emphasizing exotic non-native crops. Not that they don’t have their place, or that we can’t grow them, but we’re forgetting that we live in one of the most diverse deserts in the world. All this heritage food. Wild and full of nutrition. We are surrounded by food and medicine. It is literally everywhere. Open your mind, heart, and stomach to the possibilities that the Sonoran Desert provides.
Zotero Citlalcoatl is a Permaculture Designer, owner of Camino Verde Permaculture Services and co-owner with Jessica Citlalcoatl of Desert Monsoon Apothecary. He is also the founder of the “People’s Permaculture Movement” and can be found on YouTube and Instagram. Subs