Historic Issues in the Garden

The growing community of organic gardeners—which hopefully includes you—represents the “good guys” in several current struggles between public and private interests in gardening and commercial agriculture. Gardeners and farmers are quite different in many respects, but both are engaged in growing plants.

Mother Nature also grows plants, and has been doing so successfully since the dawn of time.

For about 10,000 years, gardeners and farmers have cooperated with Mother Nature to grow and harvest plants to eat, treat illnesses, dye fabrics, and enjoy their beauty and fragrance. They gradually developed ways to increase yields, reduce the work of growing and improve the qualities of their plants. For the most part, these changes have been compatible with natural processes.

Eventually, people adopted various technologies to improve gardening and especially farming. Beginning 4,500 years ago, various inorganic materials and organic substances derived from natural sources were used as pesticides. Major agricultural technologies include the mechanical reaper (1831) by Cyrus McCormick, and the tractor (1868), both of which brought new efficiencies.

In the 1940s, agribusiness began using synthetic chemical pesticides and great quantities of synthetic nitrogen fertilizer. In both cases, there was little or no knowledge of the impacts of these chemicals on human health or the environment.

Rachel Carson’s book, Silent Spring (1962) raised awareness of the conflict between public and private interests related to agrichemicals.

In the 1970’s, research began to development Integrated Pest Management (IPM) strategies, which rely upon natural processes and do not use synthetic chemicals. IPM became widely used beginning in the late 1970s.

During more recent decades, continuing research and development produced more selective products, including glyphosate, which soon became most widely used herbicide, worldwide.

The ancient methods of organic gardening continued throughout this history, but the seeming cost-effectiveness of uses of agrichemicals dominated commercial agriculture.

Today, we are discovering the consequences of attempts to fool Mother Nature. Insects are developing resistance to synthetic insecticides, weeds are developing resistance to synthetic herbicides, and we are discovering that at least some of these materials threaten our health.

The State of California already has listed 800 chemicals known to cause cancer or birth defects or other reproductive harm, and early this month issued a notice of intent to classify glyphosate as a carcinogen.This classification is based on the findings of the World Health Organization. See: CSG Prop 65 Heirloom EXPO FLYER Glyphosate 9-7-15.

In addition, speakers at recent conferences have called for uses of regenerative agriculture, which is a form of organic farming designed to build soil health or regenerate unhealthy soils. This practice could counteract “conventional” agriculture’s destructive practices, which include uses of synthetic chemicals. Many of those chemicals weaken or kill the soil microbiota, and thereby disrupt the natural carbon cycle and contribute substantially to global warming.

By any measure, we are now in a historic period of change, to reject shortsighted agricultural technology and return to more natural processes. Our health and the health of the environment depend on the success of this transition.

 

South African Flora

As California’s drought stretches into the future, the plants of Earth’s five Mediterranean climate zones attract gardeners’ interest and soon earn their appreciation. Many of these plants are fine additions to the landscape, offering beauty, fragrance and benefits for garden fauna as well as easy cultivation (with some exceptions) and environmental friendliness.

In today’s column, with our feet on the ground, we have an overview of the flora of one of these “summer-dry” zones: South Africa.

This relatively small country’s Mediterranean climate zone is the very small and extraordinary Cape Floristic Region. As background, botanists have identified six Floristic Regions (floral kingdoms) of the world. These are regions with distinctive plant life. The Cape Floristic Region, by far the smallest of the six, is noteworthy for very high diversity of plant life, with over 8,000 species, and very high endemism: nearly 70% of the plant species are native to the Region and nowhere else.

Much of the Region’s botanic diversity grows on the fire-prone shrub land called fynbos, which is roughly comparable to California’s chaparral. Both of these two shrub lands have shrubs with hard leaves, closely spaced on their stems.

The fynbos is the home for numerous small shrubs, evergreen and herbaceous plants, and bulbs, many of which are in three plant families.

The Protea family (Proteaceae), which includes 80 genera and 1,600 species, all in the Southern Hemisphere, and mostly in South Africa and Australia. The family name comes from the name of the Greek god Proteus, who could change between many forms. The adjective “protean” (changeable, versatile) has the same root. Plants in this family have a great diversity of flowers and leaves.

The popular South African genera in the Protea family include

  • Proteas (sugarbushes), which come in a range of heights, from three feet to nine feet, with unique compound flower heads (correctly, inflorescences) in pink or sometimes red.9-11-15 Protea
  • Leucospermums (pincushions), most reach four-to-five feet tall, with yellow, orange, pink or red flowers.

9-11-15 Leucospermum

  • Leucadendrons (conebushes), various species grow from three-to-eight feet tall; the striking silver tree (L. argenteum) reaches 25-to-40 feet tall, with “soft, silky, shimmering, silvery-green-gray, lance-shaped foliage.” The cone-shaped flowers typically are surrounded by petal-like bracts, often combining red and yellow colors.

9-11-15 Leucadendron

Australia is home to several genera of the Proteaceae, including banksia, grevillea and hakea.

The Cape heaths (Ericaceae) include some 660 species that are endemic to South Africa, and are often called winter (or spring) heather. Another 40 species, including summer (or autumn) heather are native to other parts of Africa the Mediterranean basin and Europe. Most of the Cape heaths are small shrubs, from eight inches to sixty inches in height, with attractive tubular pink flowers throughout the year.

The Cape reeds (Restionaceae). The genus Restio includes 168 species in South Africa. Various species of Restio grow from one-to-ten feet tall, with tiny flowers grouped in spikelets that comprise inflorescences. Other genera in this family of perennial, evergreen rush-like flowering plants are found throughout the Southern Hemisphere.

To view photographs of South African plants, serve the web for the plant’s botanical name and click on the menu option for images. Better yet: to experience the real presence of these plants, browse to arboretum.ucsc.edu, navigate to Visit/Gardens and Collections/South Africa, and tour the Arboretum’s South African collection in person. You could become inspired to bring South Africa’s botanical bounty into your own garden.

Carbon Farming

Climate change has been described as the consequence of the Industrial Revolution, which introduced extensive burning of fossil fuels. This practice disrupts the natural balance of carbon in the soil, the atmosphere and the ocean. Plans to slow or reduce the process of climate often emphasize reducing uses of fossil fuels.

Recently, and all too briefly, we explored the relationship between gardening and climate change. We have learned that common agricultural practices generate about one-third of the surplus CO2 in the atmosphere, making commercial farming a substantial part of the climate change problem.

Prior to the development of modern agriculture, we had organic farming, which is generally compatible with natural processes. The practices we now call “conventional” farming include driving a tractor, tilling the soil, over-grazing, and using fossil fuel-based fertilizers, pesticides and herbicides.

Similarly, farm animals once were raised in pastures, where they grazed on grasses and other plants. Today, cows, pigs and chickens are raised in tight quarters, provided grains and other feed that they work hard to digest, and must be dosed with antibiotics to maintain basic health.

These contemporary, presumably efficient methods are depleting the carbon stores in the soil, and reducing the soil’s natural ability to support plant growth and store moisture.

Soil scientists and environmentalists have been discovering land management strategies that can reduce the rate of loss of soil carbon, and even improve the rate at which agriculture can convert atmospheric CO2 into plant material and soil organic matter. When thoughtfully applied, carbon methods can add significantly to the rate of soil carbon sequestration, and actually reverse the climate change process.

Dozens of specific practices are included in carbon farming; all look like historical organic farming and common sense. The principal methods are composting, grazing by hoofed animals (ungulates), maintaining high percentages of organic matter in the soil (to feed the microbiota), supporting biodiversity, rotating crops and discontinuing uses of synthetic chemicals. The most effective practices orchestrate multiple methods in plans designed for specific circumstances.

Carbon farming, also called regenerative agriculture, should be part of the global response to the threat of climate change, but reduced burning of fossil fuels will still be important.

These promising methods for the management of agricultural lands can have substantial impacts when applied on a large scale, but they also have value when applied in residential gardens. In this column, we have advocated organic methods as beneficial to our flora and fauna. We find now that these methods also have long-term benefits to the health of the soil and the natural balance of carbon in our environment.

For more about this important topic, read Kristin Ohlson’s book, The Soil Will Save Us (2014), (which a reader recommended to me), and search the web for “carbon farming” and “regenerative agriculture.”

If you are growing plants and raising animals on hundreds of acres, try carbon farming. If not, by all means, garden organically!

Interactive Gardening

Our interactions with other persons or things can be among our most absorbing, challenging, satisfying—and occasionally most frustrating—activities. Examples include raising a child, working with colleagues, living with a spouse, cooking, and, yes, gardening.

Early uses of the term, “interaction,” dating from 1832, emphasize reciprocal action, i.e., the action or influence of persons or things on each other.

In this digital age, “interaction” often refers to the responses of computer software to a human operator’s inputs, e.g., keyboard entries, voice commands, or other forms of messaging. True human–computer interactions include the human’s responses to the computer’s output.

In this column, we are focused on gardening.

Interactive gardening means a gardener’s actions on a plant, the plant’s responses to those actions, and the influence of the plant’s responses on the gardener’s future actions.

Some gardener’s believe they can influence plant growth by talking to, or playing music to, the plant, but plant scientists tell us that while plants are very sensitive to their environment, they are unaware of their gardeners or sounds.

For a scientist’s analysis of the ways in which plants experience the world, read What a Plant Knows: A Field Guide to the Senses, by Daniel Chamovitz (Scientific American, 2012). The author reviews the research into what plants see, smell, feel, hear and remember, and how they know where they are.

Chamovitz shows that plants are aware—in highly evolved and surprising ways—of “external pressures that increase or decrease a plant’s chances for survival and reproductive success.”

For this reason, interactive gardening involves the gardener managing the plant’s environment, the plant responding to the environmental conditions, and the gardener noting the plant’s response and modifying his or her actions to achieve an intended response by the plant.

The gardener can affect all aspects of the plant’s environment, including the amount of light, heat, wind and moisture; the structure of the soil; the availability of natural or synthetic nutrients; and the presence of pests and diseases. Planting a seed involves modifying its environment.

The gardener also can interact directly with a plant, but only by touching or cutting the plant by pruning, dividing or transplanting.

For example, the Sensitive Plant (Mimosa pudica) responds to even a light touch by causing its leaves to fold or droop. This unusual response could be a defense against herbivores or insects that might be startled by the plant’s sudden movement.

As an aside, landscaping and flower arranging do not qualify as interactive gardening because the landscaper or arranger seeks to encourage responses from other humans, not from the plants.

When we consider gardening as an interaction between the gardener and the plant, we realize that the gardener’s success grows with his or her understanding of the plant’s responses to environmental conditions.

This encompasses simple responses, e.g., drooping from lack of moisture, less obvious responses, e.g., slow growth from lack of soil nutrients, and more complex responses, e.g., failure to set fruit from lack of seasonal chill.

Mastering the responses of plants to numerous environmental variables, and differences between plants from various native habitats, can be a lifelong study. Still, every gardener doesn’t need to study all plant’s cultivation preferences, or complete advanced studies of plant science. The gardener who wants to succeed and enjoy the experience should, however, learn about the needs of each plant in his or her garden.