Living Los Angeles: Tending the wilderness within

Los Angeles is very much alive. It might seem that we have worked hard to change that. Over the last century, we have covered over 60% of our land surface with houses, roads and sidewalks; in some parts of the city it’s almost 90%. We’ve laid down asphalt expanses so vast that the heat they absorb and radiate alters local atmospheric circulation. The rivers that once commanded the vast Los Angeles Basin as their floodplain are relegated to the narrowest of concrete channels. So many cumulative feats of engineering have managed to accommodate one half of the population of the 6th largest economy of the entire world onto just 0.02% of the world’s surface. This is the land we call the Greater Los Angeles Area.

We decorate this city with plant species imported from Europe, Asia, Australia and Africa, creating juxtapositions of plant and animal species unprecedented in evolutionary history. Such colourful landscapes are maintained by regular inputs of labour, gas, electricity and 50% of the water that Los Angeles transports from ecosystems hundreds of miles away through its notorious aqueduct system.

A careful observer might notice a quieter kind of activity in undesigned and neglected spaces of the very same city. Here, independent of the intention of any gardener, greenery sprouts from the cracks between things. What would happen if we treated such processes as energy to be tapped, rather than a problem to be fixed?

The gap between the resource-consuming nature of planned landscapes versus the unstoppable nature of unplanned landscapes shows how far we have to go in engineering truly sustainable cities. This article treats both types of landscape as conditions of possibility that might be re-envisioned in our evolution toward sustainable cities.

Plant species have been engineered by the process of evolution to perform specific functions within ecosystems. 

Plants provide services as diverse as food production, wildlife habitat, erosion control, carbon storage, soil building, facilitation of infiltration, flood attenuation and air and water quality improvement. In limiting the role of urban landscapes to ornamental uses, we ignore the potential for designed landscapes to provide this multitude of integrated benefits.

In the semi-arid Los Angeles basin, native plants provide such services with no other input than sun, soil and less than 20 inches of precipitation a year. Non-native plants, (even though most require irrigation), may be especially useful for food production and microclimate attenuation. The numerous services provided by plants have yet to be exploited to their full advantage in the urban context.

Permaculturalist Larry Santoyo suggests the designer’s job is to create the conditions for the desired result to be inevitable. When conditions are right, landscapes are powered by the limitless forces of nature. How can we create the conditions for urban landscapes to become effortlessly productive and self-sustaining: ecologically, culturally and economically? 

Observing plants of Los Angeles’ common land use types may provide some inspiration.

LAND USE TYPOLOGIES

Sidewalk Cracks and Empty Lots: Unstoppable Nature

Plants that grow in sidewalk cracks and empty lots serve an important ecological role. These ‘pioneers’ thrive in conditions where little else can survive. They grow quickly and reproduce in large numbers. Their roots break up hard ground, allowing water to penetrate. Completing their brief life cycle, the organic matter they leave behind enriches the soil, creating conditions for longer-lived plants to thrive.

In the urban environment, disturbance of land due to construction and other land use patterns favours pioneer plants over other species. As long as these land use patterns exist, pioneer species will be prevalent.Such plants can be considered resources rather than problems. 

Many of Los Angeles’ common weed species happen to be edible greens. Some, such as sow thistle, dandelion, mallow and purslane, are found in cities around the world. Research suggests that foraged greens may be nutritionally superior to commercially-bred equivalents.

Portulaca oleracea (Purslane)

A botanical chameleon that shares traits of desert and tropical plants, purslane is one of the most successful pioneer plants worldwide. It is well adapted to cracks in the sun-heated pavement of urban Los Angeles, where it can thrive under generous irrigation, lack of irrigation and even relatively high salinity.

Purslane was written about by Pliny and Theophrastus. It is enjoyed as a food by Australian aborigines, Russians, Greeks, Pakistanis and Egyptians and is used in Chinese medicine.

Recently, purslane is making a comeback at farmer’s markets throughout the U.S. It is recognized as a ‘superfood’ due to its exceptional nutritional content. Purslane has more omega-3 fatty acids than any other green plants (nine times more than avocado or spinach). It is high in melatonin, vitamins A, C, B, and E, and dietary minerals such as magnesium, calcium, potassium and iron.

The Residential Garden: The grocery store and medicine cabinet of the world

Los Angeles’ residential landscapes are made up of vegetation from every continent, thrown together into juxtapositions unlike any found in nature. Many of these plant species have qualities long appreciated by indigenous people around the world, whose livelihoods depended on local ecological knowledge. Learning about plant uses recognised by cultures around the world can increase the cultural literacy of Angelenos, as well as the productivity of our urban landscapes.

Carissa macrocarpa (Natal Plum)

In Los Angeles landscapes, Natal Plum is a ubiquitous evergreen hedge whose large magenta fruit are generally treated as a visual curiosity. Yet, in its native South Africa, ‘num num’ fruits are appreciated as a delicious fruit sold at roadside stands.

Carissa fruit are high in vitamins B and C, iron, potassium, copper and magnesium. With rich nutritional content and market-ready looks and taste, Natal Plum would seem poised to make a contribution to drylands food security and sustainable agriculture.

Natal Plum has eluded large-scale commercial production, even in its home country. The factors that complicate large-scale production, however, would be less of an obstacle to small-scale localised food production.

Parking Lots and Medians: Designed for neglect

Parking lots and medians are planted with species chosen for their neat appearance and minimal maintenance requirements. They are designed to withstand neglect.

Exploiting the uses of plants that are already established in such landscapes and planting other useful plants can help these landscapes contribute to biodiversity or food production, as opportunities and needs permit.

Parking lot landscaping sometimes provides opportunities for flood control and water quality improvement. Parking lots designed to maximise these benefits may incorporate some seasonal native wetland habitat.

Carpobrotus edulis (Ice Plant)

Carpobrotus originally became popular throughout southern California because of its neat appearance and minimal maintenance requirements. Today, it is notorious for crowding out native wildlife in the coastal dune ecosystems. Removal of ice plant mats will be a key part of restoring the dynamism and biodiversity of these ecosystems.

Until more beneficial landscapes one day replace the vast urban acreage currently dominated by Carpobrotus, making use of the ample food and medicine the plant provides might be a lesson in global cultural exchange. Carpobrotus is called ‘sour fig’ in its native South Africa. Its dried fruit are popular snacks sold at roadside stands.

Sour fig jam is sold in nearly every market. In South Africa, Carpobrotus is planted in home gardens for its medicinal uses. Its leaf juice contains flavonoids and tannins whose astringent and antiseptic properties make it useful for treating cuts and minor skin infections, as a gargle for throat infection or to relieve digestion problems.

Urban Agriculture: Masqueraders at the ball

Urban agriculture is in resurgence. Urban farms diversify food options in resource-strapped communities. Local food production reduces food-related transportation and improves food security in the face of climate change. Moreover, urban farms often become centres for community life.

Conventional agricultural techniques have a paradoxical relationship with wild foods. Whether practiced on the scale of commercial production or a community garden plot, the practice of tilling optimises weed production by disturbing the soil and then leaving the soil surface bare. A Berkeley study found that up to 40% of the biomass produced in organic farms in the Bay Area comprised plants considered to be weeds.

If organic and small scale farming ‘weeds’ out 40% of its output, we might do well to envision alternative approaches to agriculture. Many ‘weeds’ have been appreciated as foods for much of recorded human history. Wild foods have been found to have superior nutritional content compared to their commercially farmed equivalents (even within the same species).

Expanding our idea of what agriculture can be — what plants and spaces are worth cultivating — may allow us to more fully utilise the rich human, cultural and environmental resources of our city. Urban agriculture has the potential to contribute local employment opportunities from horticulture, processing, marketing and distribution to culinary innovation utilizing climate-appropriate food plants.

Chenopods including Chenopodium album (Lambs-quarters)

Most Americans are familiar with the chenopods available at grocery stores: beets, chard, spinach. Yet, a whole array of edible chenopods grow prolifically without fertilisers or artificial irrigation wherever there is untended soil. Wild chenopods may be relatively drought tolerant and salt tolerant. Many are table greens in other parts of the world. The most well-known of these may be lambs-quarters (Chenopodium album). Its leaves are high in vitamins A, C, B-complex vitamins and calcium.

Farmers curse that wild chenopods produce seeds and germinate continuously throughout the growing season. For gardeners and foragers, the long season during which wild chenopods are available is a blessing.

Urban/Wildland Interface: Fragile biodiversity

Seedlings of native oaks may be found growing furtively under manicured hedges throughout the city. Such volunteer plants demonstrate that conditions on the site are right for their growth. Unfortunately, despite the essential services they provide for local ecosystems, native plants may still be treated as ‘weeds’ in artificially cultivated gardens.

There are no technologies more efficient than native plants in providing ecosystem services in Los Angeles’ semi-arid climate. Lisa Novick points out that native plants have been engineered by nature over millennia in response to California climate, soils and wildlife interactions. Oaks, for example, grow several storeys tall, shade the ground, protect and build soil, facilitate infiltration and provide habitat for innumerable wildlife species, with no other input than the modest amount of precipitation that may fall each winter.

Entomologist Doug Tallamy considers native plants the foundation of the food web. The innumerable insect species they feed become food for birds, lizards and small mammals, which then become food for larger animals. Replacement of insect-rich native species by exotic plants that provide food for relatively few local insect species dramatically reduces wildlife populations overall.

Planting native species in developed landscapes that are situated near remaining patches of habitat not only replaces some of the habitat destroyed by development, but may also protect or enhance the quality of the adjacent habitat.

Quercus agrifolia (Coast Live Oak)

Native oaks generate entire ecosystems in their canopy and the soil beneath. According to the Theodore Payne Foundation, a native oak feeds up to 5,000 species of beneficial insects. Even the mulch that collects under them becomes habitat for complex communities of microorganism and microarthropods. It is believed that the mycorrhizal communities associated with the oak’s root systems increase the water-holding capacity of the soil, as well as the infiltration of precipitation. Oaks stabilise slopes and the shade they provide is a valuable resource during hot Los Angeles summers.

CONCLUSION

The ecosystem services provided by plants in urban landscapes have the potential to contribute to food security, community life, local employment opportunities and native habitat. Many urban landscape types can increase their provision of such services without significantly affecting their current uses or ornamental value. 

Activists, gardeners, researchers and designers have only begun to harness the power of urban nature. 

Vegetable gardening in residential front yards is increasingly a frequent sight. Numerous businesses grow and maintain food gardens for residents who lack time, knowledge or gardening experience. Guerilla gardening and urban foraging are more and more prevalent. Online services pair gardeners who have no land with property owners who want gardens but cannot manage their own. Organisations like TreePeople and Northeast Trees originated with grassroots tree planting efforts and now provide support to residents who want to start their own greening projects. Grassroots movements can coalesce into institutional form and even legislative action: recent state and local legislation incentivizes urban agriculture for its potential to ameliorate ‘food deserts’.

In a future city, one might imagine an entirely new set of land use types:
• Agro-ecological landscapes composed of nutrient-dense wild greens grown beneath climate appropriate fruit trees become common in residential and commercial landscapes.
• Ornamental plantings of neighbourhood parks and schools double as working landscapes of arid lands, vegetable and fruit crops. Tending these landscapes employs young urban farmers who have been trained in organic production methods. Some young farmers experiment with developing varieties of climate-appropriate food plants that have improved fruit size or ornamental value.
• Graywater water-polishing wetlands that provide native habitat for wildlife are essential landscape features of any multifamily residential unit.
• In the same multifamily residential units, courtyard air is cooled by the evapotranspiration of banana, mango and papaya trees and cut flower gardens, all irrigated by water recycled from residents’ sinks, laundry and showers.
• Neighbouring landowners collectively manage their landscapes to optimise opportunities of the site, while reducing labour costs. For example, adjacent to existing wildlands, managing multiple contiguous properties to attain local habitat goals may improve the habitat quality of each property, as well as that of adjacent wildlands. Similarly, management of multiple contiguous residential properties for food production would improve economies of scale, while decreasing costs.
• The culinary richness of wild and climate appropriate food plants becomes celebrated in local cuisine. Precedents exist in forager Tama Matsuoka Wong’s collaboration with NYC chef Eddy Leroux, Berkeley Open Source Food’s work with local chefs during Wild/Feral Food Week, and Pascal Baudar and Mia Wasilevich’s ‘wildcrafting’, which culls ingredients from the rich landscapes of the Los Angeles Metropolitan area.

Designers and planners can guide the transformation of urban landscapes toward typologies that maximise the power of urban nature while serving the needs of local communities. 

Increasing local food production and maximizing the ecosystem benefits of planted landscapes can reduce our city’s overall water and energy footprint and our dependence on the natural resources of ecosystems hundreds of miles away. 

Even in the most neglected corners of the Greater Los Angeles Area, the unstoppable power of nature is evident. As we design to harness this power, the landscapes of our city may begin to more clearly reflect the richness of our human communities and our regional biodiversity.