Gardening’s Underlying Science


We appreciate our gardens for their beauty and natural vigor, even as we know, deep down, that each plant is a wonder of science.

Well, perhaps that thought hasn’t entered your thoughts, recently, but it’s still true.

You might think we don’t need to dig into the science behind plant growth, as long as we keep them fertilized and watered and they keep growing. That’s not necessarily true!

I’ve been gaining interesting information about the science that underlies garden plants. One of the very good sources of that information is horticulturist Linda Chalker-Scott, Ph.D. She has published fine research reports, taught a lot of university courses, and has communicated a lot of plant science to home gardeners through Master Gardener programs in the State of Washington and her writing.

Her writing for lay readers has been published in several books and periodicals, and on The Garden Professors, a blog on which she and several colleagues share their expertise and opinions. This website ( includes fascinating reports of gardening myths.

Misconceptions abound in the gardening community.

I first became aware of Chalker-Scott’s contributions through two of her books, The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010).

Her newest book is How Plants Work: The Science Behind the Amazing Things Plants Do (Timber press, 2015).

The Informed Gardener

In How Plants Work, she presents basic concepts of plant biology: cells, roots, nutrition, photosynthesis, leaves, seasonal cycles, growth patterns, pruning and propagation. (This very brief list of the book’s topics doesn’t convey the depth of her presentations. See the book for the full information.)

Dr. Chalker-Scott has written these chapters with her well-established commitment to communicating her scientific knowledge to non-scientific readers. She has managed to present the science effectively without “dumbing it down.” Gardeners with limited backgrounds in biological science can understand and appreciate this information, but will have to stay focused and perhaps read some passages more than once. I certainly did!

The book addresses some gardening myths, which I find always interesting, but emphasizes the positive message: knowing “how plants work” is the foundation of successful gardening.

To encourage you to read this book, I will share one of the book’s gardening myths, and an example of its garden science nuggets about which gardeners should know.

Myth: Landscape fabric blocks weeds while letting water and oxygen to pass through.

Reality: These fabrics soon become clogged with soil particles, and block the movement of water and oxygen. Meanwhile, weeds become established on top of the fabric, and some aggressive varieties manage to poke through.

Science Nugget: All plants have primary compounds that are required for growth and development: sugars, DNA, fats and proteins. They also produce secondary compounds that defend against pests and diseases, or that attract pollinators, or have other properties that are currently unknown. Chalker-Scott describes several kinds of secondary compounds and reports that every plant produces one or more unique compounds, and that scientists know about less than ten percent of the compounds that plants make.

We think we know a lot about the plants in our gardens, but we have a long way to go.


Restoring Soil

Several people commented on last week’s column on the carbon cycle. All endorsed the concept of restoring garden soil, to support its natural ability to sequester carbon.

One reader had questions about how to go about restoring garden soil. This is a Big Topic and you, good reader, might have your own questions, but you also might share his interests. My brief responses are below. Visit for more details, including plant suggestions.

Q. Plow the grass under?

A. Losing the thirsty lawn is a good first step, because such monocultures are not appealing to wildlife. Plowing, however, could both promote re-growth of the grass and bring dormant weed seeds to the surface. A better approach is to kill the grass over several sunny weeks by covering it with clear plastic (solarization), or with newspaper or cardboard (smothering).

For information on Soil Solarization for Gardens & Landscapes, visit the University of California’s Integrated Pest Management webpage on the topic. The presentation emphasizes pest control; in this context, unwanted turf grass amounts to a pest.

The California Native Plant Society has Detailed lawn removal advice.

Q. Plant different grass?

A. Yes! California native grasses can provide the basis of an attractive meadow, which is more casual than a manicured carpet of turf grass. A meadow has unique aesthetic appeal; supports a variety of wildflowers and wildlife; requires little water, infrequent mowing, and no chemicals; and helps to restore the soil.

Kids on Native Grass Lawn

Lily Baker’s front yard in San Jose
features a native grass lawn.
California native grasses help restore the soil.

For information on several California native grasses, visit the Tree of Life Nursery’s web page, “Masses of Grasses.”

A very good book by Carol Bornstein, David Fross, and Bart O’Brien is Reimagining the California Lawn: Water-conserving Plants, Practices, and Designs (2011).

Q. Grow more trees?

A. Absolutely! Trees and large shrubs are attractive additions to the landscape, valuable participants in the carbon cycle, and welcomed by all forms of wildlife. Invest a little research to select trees will thrive in your climate, and grow to an appropriate size for your landscape. Again, California natives are good choices.

A good introduction to California native trees and larger shrubs is available from the non-profit Nipomo Native Garden, which has produced a web page, “Native Trees for Landscaping and Wildlife.”

Q. Eliminate ground cover in favor of something with deeper roots?

A. Ground covers are any plants that hug surface or rise to any height up to four feet. Most importantly, they protect soil and soil microbiota from baking in the sun, or eroding. During the fall and winter, plant seasonal cover crops that draw nitrogen from the air and store it in their roots. Examples of such “nitrogen-fixing” plants include peas, beans, and clover. In the spring, before your cover crop sets seed, till the plants under to decompose and release their nitrogen into the soil to support the growth of other plants.

Deeper roots mean better drought-tolerance: deep-rooted plant can find moisture far below the surface. Such plants are generally preferable in the landscape, all other factors being equal.

The depth of roots varies among plants, reflecting adaptation to the plant’s environment. Among weedy grasses, for example, Annual Bluegrass (Poa annua) has roots only about right inches deep, while Bermudagrass (Cynodon dactylon) can grow to 60 inches deep in search of water.

Infrequent, deep irrigation encourages all plants to develop deep roots and drought tolerance. A common error with automatic irrigation systems is to schedule frequent, brief periods of watering. This practice encourages shallow roots, ultimately increases overall water usage and leaves plants vulnerable to dry periods.

Q. Shallower roots?

A. The advantage of shallower roots is that plants growing in arid climates have immediate access to occasional rains. Succulent plants have adapted to such conditions by developing shallow roots and the ability to store scarce moisture in their leaves, stems or roots. For this reason, gardeners often appreciate succulent plants for both drought tolerance and landscape appeal.

The New California Garden, which we envision here, features meadow grasses and succulent plants: a good time to start is now.

Gardening to Reverse Climate Change

The threat of climate change has become a concern among scientists, environmentalists and gardeners (who might wear all three of these hats, of course). In the search for solution to this problem, these three interested parties have common ground, as we explore in this column.

As background, our climate is changing as a result of a disruption of the Carbon Cycle.

On Plant Earth, a fixed amount of carbon cycles through different forms: liquid, solid, or gas.

Carbon enters the atmosphere from several sources, including respiration of animals and plants, decay of animals and plants, eruptions of volcanoes, and releases of dissolved carbon dioxide (CO2) from the oceans.

Plants absorb carbon dioxide (CO2) from the atmosphere, and use photosynthesis to release oxygen back into the atmosphere and convert carbon into sugars that support the plant’s above-ground growth. At the same time, up to 40% of the CO2 goes to the plant’s roots, to feed soil microbes. The microbes assist the plant to acquire nutrients through its roots, and lock (“sequester”) carbon into the soil for very long periods.

The Carbon Cycle supports Earth’s climate and enables the growth of plants and literally all other living things.

Carbon Cycle

Credit: NASA/Globe Project

In the diagram above, notations in blue indicate pools of carbon and notations in red indicate fluxes of carbon, both quantities are measured in petagrams.

This complex natural process balances the amount of carbon in liquid, solid and gas forms. Vast amounts of carbon are stored in the soil and fossil fuels, and much smaller amounts are stored in the atmosphere, the oceans, and plants.

During the Industrial Revolution (1760 to c. 1830), humans began burning fossil fuels, cutting down forests, draining wetlands, converting grasslands to large-scale crops, paving paradise, and applying synthetic chemical fertilizers and pesticides. These activities have been disrupting the Carbon Cycle and altering this important balance.

The consequences include degraded soil with reduced ability to capture carbon, an excess of carbon in the atmosphere, the acidification of the oceans, and other effects, none of which are beneficial to living things (including us).

The broad term, climate change, encompasses all these negative effects.

Restoring the natural Carbon Cycle could reverse climate change.

Restoration requires feeding the soil with organic matter and planting cover crops to protect the soil from temperature extremes and erosion. In short, the solution is based upon regenerative, organic agriculture.

This strategy must be employed on a global scale, but we all should understand the Carbon Cycle and support this process of soil restoration in our own gardens and in our individual contributions to relevant public policy. Substantial private interests are invested in fossil fuels, “conventional” monoculture agriculture that depends upon synthetic chemicals, and other industrial methods that are changing our climate. They can be expected to resist this strategy of working with nature, so eventual success requires our vision and long-term commitment.

Each gardener could participate first in his or her own garden. That would be a fine way to celebrate our independence from, in this context, commercial interests.

Continue reading

Agave: Another of Mexico’s Gifts to Gardeners

A recent column provided an overview of the genus Echeveria, called “Mexico’s Gift to Gardeners.” Today, we take a look at the genus Agave, another of Mexico’s gifts to gardeners, with value for larger settings.

Agave species grow naturally through the southwestern United States, Mexico and Central America, Columbia and Venezuela in South America, and the Caribbean islands.

All Agaves are monocarpic, i.e., they die after flowering. Unlike many annual plants, Agaves can grow for several seasons before flowering, setting seed and dying. For this reason have been called “multiannual.” They have also been called Century Plants, but they flower and set seed in much shorter periods, generally when conditions are right to support propagation.

There are two basic vegetative types of Agaves. One type produces offsets (called pups or babies) either in the leaf axils or through underground stems. The other type, called the solitary Agaves, propagates only by producing seeds.

These types are important for placement in the landscape. An offsetting type Agave needs ample space to allow for full development of a larger cluster of plants, while a solitary type Agave needs only enough space to accommodate its mature size.

Agaves generally consist of leaves arranged in a spiral, forming a rosette. The leaves might be thick or thin, succulent or fibrous. Some Agaves have smooth leaf edges, while others have sharp teeth along both sides of the leaf. Some species have leaves with terminal spines, which might be stout and quite sharp.

The rosettes come in several size categories, depending on the species. The smallest can be three inches tall and four inches across, and the largest can be ten feet tall and twelve feet across. Likewise, the flower stalks vary in several characteristics, including height that in some species, e.g., A. americana, can reach up to thirty feet.

There are over 200 species of Agaves. Of these, about 80 are found in gardens, and only about ten species are commonly grown. The typical home gardener in the Monterey Bay area will be familiar with three or four species.

Agave americana, which grows to large dramatic form, is widely cultivated worldwide for its ornamental value. The rosette of A. americana can spread to six-to-ten feet in diameter, and its flower stalk, as noted above, can reach thirty feet. At east six cultivars are available, with different patterns of white or yellow striping on the green leaves.


Agave americana ‘Marginata’

Agave attenuata gets its specific name from the leaves that shrink to a point. This plant has an unusually curved stem, which is revealed as leaves age and fall off. It develops a rosette of six-to-eight feet in diameter, and produces a flower stalk up to ten feet long. The stalk typically will reflex towards the ground, then arch upward again. This growth pattern gives the plant the common names, the Fox Tail Agave or Lion’s Tail Agave or Swan’s Neck Agave. Because this plant lacks teeth along the leaf margins, or terminal spines, it presents no hazards in the garden.


Agave attenuata Credit: Annie’s Annuals

Agave tequilana, the Blue Agave, produces large amounts of sugars, mostly fructose, in the core of the plant, making it particularly suitable for preparing Mexico’s well-known tequila and other alcoholic beverages. This plant can grow to over seven feet tall, and produce a stalk up to sixteen feet high. A. tequilana has as much landscape value as other Agave species, but is most widely grown commercially.


Agave tequilana (Blue Agave)


Agave victoriae-reginae, known as Queen Victoria Agave, is a smaller plant, growing slowly to 12 inches tall and 18 inches wide. It is popular as an ornamental for its streaks of white on sculptured geometrical deep green leaves. The leaves lack marginal teeth, and sometimes have short terminal spines. The flower stalk, which can reach up to fifteen feet, displays reddish-purple flowers. This is the only solitary type agave of the species listed here.

Screen Shot 2015-06-27 at 8.59.57 PM

Agave victoria-reginae

Agaves are drought-tolerant, easily grown plants that can bring dramatic architectural forms to the landscape.

Million Pollinator Garden Challenge

We are in the midst of National Pollinator Week (June 15–21)! An unprecedented group of twenty-four conservation and gardening organizations has formed the National Pollinator Garden Network and, with First Lady Michelle Obama, launched the Million Pollinator Garden Challenge.


The Network challenges the nation’s gardeners to create one million additional pollinator gardens by the end of 2016.

This campaign encourages home gardeners to help reverse the decline of honeybees and native bees, butterflies, hummingbirds and other pollinators. This extraordinary initiative underlines the importance of pollinators to our food supply and invites home gardeners to take effective personal action even as the nation’s Pollinator Task Force mobilizes more than fifteen federal agencies to improve pollinator health.

In a recent column, we urged keeping your garden free of synthetic chemical pesticides and herbicides, and using less-toxic alternatives. The Pollinator Partnership (, a member of the new Network, offers specific advice:

  1. Plant for Pollinators (the website includes a link to a cellphone app that lists 1,000 pollinator friendly plants native to the United States)
  2. Reduce or eliminate the impact of pesticides.
  3. Register as a SHARE site (see more about this below)
  4. Reach out to others – inform and inspire
  5. Buy local and organic produce, including honey
  6. Conserve all of our resources; use less and reduce your impact.
  7. Support the work of groups promoting science based, practical efforts for pollinators

The Network concurs with these recommendations, as expected, and adds these complementary ideas:

  1. Provide a water source
  2. Situate your garden and/or plants in a sunny area with wind breaks
  3. Create large “pollinator targets” of native or non-invasive plants
  4. Establish continuous blooms throughout the growing season

Once you establish your pollinator habitat garden, visit to register your garden on the Pollinator Partnership’s SHARE site. Adding your garden to the site’s map of the United States gives you personal bragging rights as a friend to pollinators and supports the effort to encourage others to participate in the Million Pollinator Garden Challenge.

The website for the Challenge ( provides links to each of its members, and most (or all) of these groups identify pollinator-friendly plants.

Still, because gardening is specific to location, Monterey Bay area gardeners should focus on plants to native to the local region. To find such plants, visit these websites:

California Native Plant Society 

Las Pilates Nursery

Xerces Society

Join the Million Pollinator Garden Challenge. The bees and other pollinators will thank you, and your garden will be richer for the effort.

Rain Gardens – Advanced Water Conservation

Most gardeners have learned that large percentages of residential water usage occur outdoors, mostly as a result of irrigating lawn grass and other plants, and have adopted water-saving practices: replacing thirsty lawn grass with naturally drought resistant perennial plants, especially California native plants, using efficient drip irrigation, and mulch. These strategies involve relatively low expense, depending on implementation.

Some gardeners have gone to the next stage of water conservation, which includes water catchment and grey water recycling. These strategies require equipment, and its installation, both of which could lead to some initial expenses. A 5,000-gallon water tank, for example, would be a substantial investment, but one pays off through long-term water savings or even fire protection.

Today’s column introduces percolation ponds as another stage of water conservation.

When we are fortunate enough to have rain, much of the water from roofs and paved areas runs to storm drains, which in the Monterey Bay area lead eventually to the sea. An efficient storm drain system avoids flooding, but often delivers pollutants into the ocean. A better approach is to direct the runoff to the soil, which filters the pollutants and leads the water into the aquifer.

This approach involves the development of a percolation pond, which is simply a low area that collects and holds runoff so that it percolates into the ground.

The principal objectives for percolation ponds are to filter runoff to minimize pollution, recharge local groundwater, and conserve water.

To include a percolation pond in your garden, find a naturally occurring low area (or create one) that is at least ten feet away from your home and any existing septic field. This separation is needed to avoid having water migrate towards your foundation, or to interfere with any utilities close to the house.

Rain Garden - Sentinel

A rain garden by a driveway in Pacific Grove. Credit Dona Johnsen Landscape Archietcture



A rain garden away from the (east coast?) residence. Credit: EPA:gov


The percolation pond should have good drainage, so that it holds water for no more than forty-eight hours. A retention pond, by contrast, holds water for longer periods, and could be designed as a water garden or bog garden.

Determine the surface area of the percolation pond to reflect the surface area of the capture area and the soil type. For example, multiple the surface area of your roof by 20% for sandy soil, 33& for loamy soil, and 45-60% for clayey soil. If you are creating a percolation pond, the bottom layer ideally should consist of about 60% sand, 20% compost and 20% topsoil. This composition would provide effective filtering of the runoff.

Then, adjust downspouts or a sump pump outlet to direct the water into the percolation pond. Depending on the situation, a bioswale could be used to direct the runoff to the percolation pond. A bioswale is a drainage course with gently sloped sides (less than six percent) and filled with vegetation, compost and/or riprap.

In areas that receive regular rainfall, the upper layer of the percolation pond can be planted with deep-rooted perennials, which can flourish under occasional deep soaking, followed by relatively dry periods. These features are called “rain gardens.”

In California, where we need to protect and restore our aquifers, and have current drought conditions, the upper layer might emphasize decorative stones, which can slow the flow of water that might otherwise overflow, and promote percolation. California native plants, once established, would do well in a percolation pond, and also provide both an attractive appearance and environmental benefits. Continue reading

GMO Controversy

I’ve been reading lately about genetically modified organisms, commonly referred to as GMOs. The preferred term is genetic engineering (GE).

There are strong feelings about whether GE technology is good or not so good for people, for the environment, or for the future of food.

These days, given the resources of the Internet, we can read a seemingly inexhaustible series of opinions about GE foods, and be tempted to escape the controversy by simply adopting one or the other extreme position.

The controversy has narrowed down to the issue of labeling GE foods. Those in favor say shoppers should know what they are buying, while others insist that there’s no reason to label GE foods, and are willing to put a lot of money into persuading voters of that perspective.

In my search for truth, I just read Steven M. Drucker’s 511–page book, Altered Genes, Twisted Truth (2015). Drucker, a Berkeley-educated public interest attorney, has written and spoken extensively on genetic engineering and related topics. His book’s subtitle presents his central message: “How the venture to genetically engineer our food has subverted science, corrupted government and systematically deceived the public.”

Drucker builds his thesis with detailed and specific references to respectable sources, including highly qualified scientists and government officials. As a lawyer, he surely selects supportive sources, and presents a convincing case. Here are some of his main points.

Many scientists and government officials have advocated the promise of genetic engineering to enable commercial agriculture to meet global needs for the volume and nutritional quality of food. Still, there is literally no evidence that GE foods are more productive or more nutritious than conventional foods, despite contrary claims. In reality, GE technology has been used primarily to produce crops that can tolerate the herbicide Roundup, which kills all plant life other than the GE crops.

The advocates’ early enthusiasm for this technology led to a waiver of legally required tests to demonstrate the safety of new food products. This waiver was based on the argument that GE foods are no different from conventional foods, and are “Generally Recognized as Safe” (GRAS). But hundreds of scientists regard GE technology as dramatically different from historical methods of plant hybridization and selection, and express concerns about the safety of GE foods. While people do not immediately become ill from eating GE foods, several studies have shown that they could have long-term negative impacts on human health.

Finally, genetic engineering, which has been called a precise method to modify organisms, is really a form of crude “hacking.” Scientists have a very limited understanding of the complex interactions of genes, and, in their ignorance, they are fooling around with Mother Nature.

Drucker advocates the elimination of GE food products as “inherently high-rick” and unable to “conform to the requirements of food safety laws, the standards of science, or the protocols of information technology.” He contends that this could be accomplished by simply enforcing the food safety law of 1958. His preferred alternative is fuller development of environmentally friendly, sustainable and natural methods based on time-honored practices of organic agriculture.

As a growing numbers of food retailers and restaurants adopt “GMO-free” food products, and their customers choose organic foods (which are GMO-free, by definition), the technology could fade away. We’ll see.

A related book, “GMO Myths and Truths,” is available as a free download from the website, EarthOpenSource. This is second edition, dated 2014. The authors of this 330+ page book are John Fagan, Ph.D., Michael Antoniou, Ph.D., and Claire Robinson, M.Phil. The book is subtitled “An evidence-based examination of the claims made for the safety and efficacy of genetically modified crops and foods.”

Echeverias: Mexico’s Gift to Gardeners

After a recent silent auction of succulent plants, I brought home a fine specimen of Echeveria agavoides, which is one of the most popular species of the genus Echeveria, which includes 130 species. Plant hunters are finding and identifying additional species in Mexico’s mountainous terrain, where the plants are difficult to access and study.

The generic name honors Mexican botanical artist Atanasio Echeverria, who made some of the first drawings of the plant around 1787. My plant’s specific name, agavoides, means “looking like an agave.” The common name for this plant is Molded Wax Agave. Note that agaves are members of an entirely different botanical family.

Echeveria agavoides

Echeveria agavoides


The fleshy, succulent leaves of all Echeverias form rosettes, but the genus includes plants of many different sizes, leaf and blossom colors and special characteristics, e.g., frilly or bumpy leaves. The plants grow during the summer months, and are dormant from November through February. Plants may be evergreen or deciduous, and all are polycarpic, meaning they may flower and set seed many times during their lifetimes. (Monocarpic plants die after flowering.)

Many gardeners’ first contact with this genus is with “hens and chicks,” which is a common name for E. elegans, E. secunda and other plants.

Echeveria species are generally easy to propagate by separating offsets, rooting leaves, or planting seeds. The species also can be crossed easily with each other and even with species from some other genera, e.g., Graptopetalum, Pachyphytum and Sedum.

Growers have created many hundreds of generic and intergeneric hybrids. Hybridizers have named and formally introduced the more attractive cultivars, but have also released many of the less successful cultivars into the market. Hybrid plants are not propagated from seeds, but only by asexual methods, i.e., rooting offsets and detached leaves.

Selected variants within a species also can be cultivars. E. agavoides, for example, includes two popular cultivars: ‘Lipstick’, which has a rosettes in clumps that are 6 inches tall by 8 to 12 inches wide with apple-green leaves with vivid red-pink edges, and ‘Ebony’, which is similar in size, with gray-green leaves that have vivid red edges that, when grown in bright sun, blend in a dark red terminal spine.

‘Ebony’ is a natural hybrid that can be difficult to grow and propagate. In the silent auction ‘Ebony’ attracted more and higher bids than my choice, which looks to me to be ‘Lipstick’.

Excellent books about Echeverias include “The Genus Echeveria” (2008) by John Pilbeam and “Echeveria Cultivars” (2005) by Lorraine Schulz and Attila Kapitany. Another good source of information is the website of the Monterey Bay Area Cactus and Succulent Society. The Society is the local affiliate of the Cactus and Succulent Society of America.

Echeverias are available in a variety of forms, and all are easy to maintain and propagate, drought-tolerant, and interesting in color and form. They can be a fine addition to the garden, where they will develop the best colors, or an indoor container. Look for them in your local garden center or online.

Protecting the Pollinators

The next time you are in your garden, tell the bees a national strategy now exists to protect their health.

The document, dated May 19, 2015, responds to President Obama’s memorandum of June 19, 2014, establishing the Pollinator Health Task Force, co-chaired by the Secretary of Agriculture and the Administrator of the Environmental Protection Agency, and including representatives of fourteen other federal agencies. The president asked for a report in six months, but it required eleven months.

Monarch Butterly

Monarch Butterly

Several federal studies on pollinator health had already been conducted, and most observers recognized that the decline of honeybee and butterfly populations was resulting from several factors:

Loss of Habitat. The use of Roundup to kill weeds in crop fields also has been eliminating milkweeds (Asclepias tuberosa) that Monarch larvae eat.

Exposure to Chemical Pesticides. The use of neonicotinoid pesticides (“neonics”) also has been killing honeybees and leading to Colony Collapse Disorder, and perhaps killing birds as well.

Attacks from Pests. The Varroa destructor is a tiny parasitic mite that first appeared in the United States in 1987. It infests bee colonies and feeds on bee blood.

Other threats to pollinator health include loss of nutritional forage, diseases, and even stresses related to trucking beehives to pollinate agricultural crops.

The Task Force report addresses four themes: research on pollinator losses, public education and outreach, improving pollinator habitat, and developing public-private partnerships to carry out these activities.

The Task Force also identified three target outcomes:

  • Reduce honeybee colony losses by to no more than 15% within ten years;
  • Increase the Eastern population of Monarch butterflies to 225 million butterflies by 2020;
  • Restore or enhance 7 million acres of land for pollinators over the next five years.

The Task Force, working with numerous federal agencies, has developed a series of action plans and resources to pursue these intended outcomes. It also has committed to annual assessments of progress toward these goals.

Another bureaucracy has been created!

Bee-friendly organizations have been less than enthusiastic about these plans. For example, the Xerces Society said, “The national strategy includes valuable long-term plans that could, over time, strengthen the pesticide regulatory system. But it fails to offer pesticide mitigation to address issues currently facing pollinators.”

Similarly, the Center for Food Safety said, “the plan is unfortunately too weak to actually accomplish these goals.” The Center called for speedy action to reduce uses of chemical pesticides and herbicides that have been identified as threats to pollinator health.

We’ll watch for the results of these action plans. We would like to tell the bees that the federal strategy is working.

Meanwhile, help to protect our hardworking pollinators by keeping your garden free of synthetic chemical pesticides and herbicides, and using the less-toxic alternatives. For more ideas, the Pollinator Partnership has provided,  “7 Things You Can Do For Pollinators.”


Another bee-friendly group that advocates reduced uses of neonics is Beyond Pesticides.

California Master Gardener Handbook, 2nd Edition

The California Master Gardener program has released a major revision of its handbook for gardeners.

MG Handbook

In this column, we look between the covers to see if this book would be helpful to you.

The University of California’s Cooperative Extension program has been training Master Gardeners since 1980, and has produced many useful publications. UC Cooperative Extension “brings practical, unbiased, science-based answers to problems across California.” It serves California’s agricultural industry, mostly, but the Master Gardener program works with home gardeners, providing information and training in gardening, land and water management, and healthy living.

Many UC Cooperative Extension publications are rather technical, and oriented to farming on a large scale, but the California Master Gardener Handbook has been designed for both master gardeners in training and other serious home gardeners.

The first edition of the Handbook, which was published in 2002, struck me as a compilation of publications that were intended originally for farmers. That’s OK, because the advice for farmers is valid for home gardeners as well, if they skip sentences like this one from the Berries chapter: “Set heavy posts at least 2 feet into the ground at each end of the row. Set lighter posts about 20 to 30 feet apart in the row.”

The new second edition (2015) has some similar content, but a significant amount of new material is clearly aimed at home gardeners. All of the content is easy to understand, and well supported with clear photos and illustrations.

Dennis Pittenger, a veteran of the Master Gardener Program, edited the Handbook and also contributed several chapters; an additional 25 educators are acknowledged as authors of specific chapters. Much expertise is represented between the covers of this book.

The Handbook includes 756 pages, which can be categorized as follows:

  • General Horticulture (30% of the pages): Chapters include Introduction to Horticulture, Soil and Fertilizer Management, Water Management, Plant Pathology, Insects, Weeds, Pests, and Diagnosing Plant Problems.
  • Ornamentals (22%): Plant Propagation, House Plants, Lawns, Woody Landscape Plants, Landscape and Garden Design, and Poisonous Plants.
  • Edibles (40%): Home Vegetable Gardening, Grapes, Berries, Temperate Tree Fruit and Nut Crops, Citrus, Avocados.
  • Additional chapters: Overview of the California Master Gardener Program, Useful Conversions, Glossary, and Index (39 detailed pages!).

The Handbook complements UC Cooperative Extension’s online publications ( and Sunset’s Western Garden Book, which the Handbook mentions respectfully.

I’ve always thought of a “handbook” as a publication that fits in the hand, and is suitable for ready reference in the field. Indeed, such books have been called vade mecum (which is Latin for “go with me”). This 4.5-pound tome might be called, more appropriately, a gardening encyclopedia, but by any other name it would still be a valuable reference for a serious gardener’s library.


Both books are available on

California Master Gardener Handbook, 2nd Edition

The New Western Garden Book: The Ultimate Gardening Guide