Landscaping with Succulents

As we await El Niño rains, the Monterey Bay area’s familiar rainy season is already late in starting, and we feel the pull of long-term perspectives on gardening.

Let’s consider landscaping with succulents plants, which are gaining appeal for their interesting foliage forms and colors, ease of cultivation and propagation and of course drought tolerance.

Many succulent plants can hold their own in the garden as specimens or aesthetic statements, but when we group several plants, they relate to one another in various ways and we have a landscape, either by design or by chance.

Tiered Succulent Display

Tiered Display of Succulents in Sidney, Australia

Landscaping by chance is often popular, but with a little planning, gardeners can succeed with more deliberate methods.

Designing with plants involves individual preferences and styles, which we always respect. There are, however, a few broad guidelines to consider.

The first of these is “taller plants in back,” which is about visibility. Take the time to learn the mature height of each plant. Here is information sheet from succulent expert Debra Lee Baldwin, listing popular succulent plants by height: Instant Gardens.

Another organizing guideline is to group plants by their watering needs. This technique, called hydrozoning, works with nature (always a good idea!) and makes garden maintenance easier.

Using this technique requires knowing the watering needs of the succulent plants in your landscape. All succulent plants need some water, particularly during their growth periods. They need much less during dormancy.

The two broad categories of succulent plants are the “winter dormant,” i.e., plants that grow during the spring and summer, and the “summer dormant,” i.e., those that grow mostly during the fall through early spring. Here is a link to winter dormant and summer dormant succulent plants.

The landscape designer also could group plants by county of origin. Such grouping is a step toward creating plant communities, which are combinations of plants that are found in natural settings. Such combinations reflect the plants’ common needs for soil, exposure, climate and other factors. Gardening in this way involves detailed cultivation methods. Grouping plants by country of origin is relatively easy, while respecting nature and developing an interesting landscape. The avid gardener can discover a plant’s country of origin from some books and plant labels, or by entering the plant’s botanical name in

Finally, consider combining succulent plants with grasses, which are another category of drought-tolerant plants. Grasses typically respond to severely dry conditions by going dormant, rather than by storing moisture, and grass-succulent combinations are seen in natural settings. The benefit of combining succulents and grasses is primarily in the aesthetic effect of contrasting the succulent’s fleshiness with the grass’s wispiness. To learn more about grasses, see the book, The American Meadow Garden (2009), by John Greenlee and Saxon Holt.

For more comprehensive guidance, Debra Lee Baldwin’s book, Designing with Succulents (2007), provides inspiring ideas for planning your own succulent garden area.

Preparing for long-term water shortages certainly includes defensive strategies, but your preparations can include landscaping with succulents as an absorbing and creative exercise.

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.

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.

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

Gardening Close Up


We garden on different perspectives: specific when studying individual plants, and general when designing a landscape. We can regard gardening as a continuum with many points between its ends. This range of possible perspectives deepens our interest in gardening.

With all that in mind, where does the survey of a genus belong on this continuum? That thought came to mind during a recent talk by Brian Kemble, Curator of The Ruth Bancroft Garden in Walnut Creek, specializing in succulent plants.

Ruth Bancroft established this extraordinary garden in 1972 as her private collection. It was the first garden supported by the Garden Conservancy, and in fact inspired the formation of that nation-wide organization. The garden was opened to the public in the early 1990s and soon became managed by a non-profit corporation.

Brian Kemble 3-2015

Brian Kemble, Cactus & Succulent Horticulturist

Kemble has been involved with the garden continuously since 1980, and has brought his considerable knowledge of horticulture and his expertise in succulent plants to the cultivation and development of the garden. Ms. Bancroft, now 106 years of age, maintains her interest in the collection.

Kemble spoke to the Monterey Bay Area Cactus and Succulent Society, in Watsonville. His talk focused on the genus Gasteria, a South African member of the Aloaceae plant family, which includes other popular genera: Aloe, Bulbine, Haworthia and others.

The name of the genus Gasteria reflects its flowers, which to some observers are stomach-shaped (“gaster” is Latin for “stomach). The flowers hang from inclined long racemes, which can includes clusters of 100 or more flowers. The flowers range in color from pink to vermillion with yellow-green tips.

The genus includes 22 species, with rosettes ranging in size from the diameter of a nickel coin, to those with leaves a meter long.

Gasteria acinacifolia

This is a Scimitar-leaved Gasteria (G. acinacifolia), displayed at the meeting of the Monterey Bay Cactus & Succulent Society, as part of the monthly mini-show. (It won a prize in its category!)  This is the tallest of the Gasteria species, native to the Eastern Cape of South Africa.

Kemble showed examples of several Gasteria species, each of which is native to a specific area of South Africa. He also showed several hybrid forms, including at least one that he developed himself.

Gasterias are relatively easy to propagate from seeds, divisions or leaf sections. They are also readily crossed with other plants in the Aloaceae family, so we have cultivars called xGasteraloe or xGasterhaworthia.

Kemble provided an expert overview of this interesting genus Gasteria. Some members of his audience might have been inspired to collect different species of the genus, but others most likely learned about how any given Gasteria fits into the larger botanical context. This knowledge adds in subtle ways to the enjoyment of gardening.

To learn more about Gasterias and other succulent plants, visit the web site of the Monterey Bay Cactus & Succulent Society, and click on
Specific Resources. Gasterias, as you will recall, are in the plant family Aloaceae.


Bare Root Trees and Shrubs

One of the best bargains in gardening is planting bare root trees and shrubs. And now is the time to do just that.

Bare root trees are dormant, by definition, and not attractive in the usual way, but they are excellent candidates for addition to your garden.

Bare Root Tree

Click to Enlarge

I have often written of the advantages of buying mail order plants, to draw from a wider selection than local garden centers can offer. That’s still a good practice for many plants, although there are drawbacks, as well: mail order buyers need to confirm that the plant of interest is right for their garden, particularly in terms of winter temperatures. Some tropical plants will not survive even the moderate winters of the Monterey Bay area, and some require more winter chill than they will receive in our climate, and will not blossom or fruit well here.

Years ago, eager to start a small orchard of antique varieties of apple and pear trees, I ordered ten bare root plants from a mid-west nursery, only to watch them struggle and eventually fail for lack of winter chill. Purely by chance, one tree, a Cox’s Orange Pippin, managed to survive my garden’s USDA zone and is producing very tasty apples to this year. That tree stands to remind me to do my homework before ordering mail order plants.

The hazards of selection are less important during bare root season because local garden centers are able to stock very good inventories of bare root trees and shrubs that are right for the local climate.

Despite the best efforts of garden centers, the economics of stocking containerized plants limit inventories of plants in pots: they cost more to ship and require more space, and offered at twice the price of the same plant in bare root.

Conversely, mail order suppliers (which still might offer a greater range of choices) can ship wholesale orders of bare root plants efficiently to garden centers, but have to recover the greater costs of shipping small quantities of plants to retail purchasers. So, for individual gardeners, the mail order price could be higher than the garden center price.

Additional benefits of buying bare root plants include larger root mass, according to researchers, easier to move and plant without soil and container, and faster growth because they adapt easily to local soil as they come out of dormancy.

The range of options at a garden center could include ornamentals, fruit trees, roses and berries. Many other shrubs could be offered in bare root form, as well, with the same advantages, but I have seen little development of that market.

When selecting an ornamental or fruit tree, look for a straight trunk, evenly spaced branches (if any), good spread of healthy-looking roots that have been kept moist, and a complete lack of any wounds or disease.

Many garden centers also offer espaliered fruit trees that have been developed by grafting branches in the right places, rather than by the time- and labor-consuming process of training. Some espaliered dwarf apple trees include grafts of several apple varieties, to produce a healthy young tree that will both fit a tight space in the garden and produce a selection of applies that ripen at different times during the season.

It is important to plant bare root specimens before bud break, so there is a small window of opportunity for the lowest prices. Don’t delay!

Roses for Foggy Areas

Q. Are there any hardy roses you would suggest I could plant that will survive Pacific Grove’s sandy soil and fog?

I enjoy your column.

December 2013

A. In December, it’s appropriate to strip leaves from roses to encourage dormancy. Just pull them off by hand and rake up under the rose bush to minimize any disease and over-wintering pests.

Treat the sandy soil and fog as two different issues. (They are both manageable.)

Sand in the soil helps drainage (which roses and most other plants appreciate), but there can be too much of a good thing. The sand content of your soil should be between 10% and 30%. I recommend analyzing soil texture so that you will know what you have. Here is a link to Fine Gardening magazine article, “How is Your Soil Texture?” that describes a simple procedures that you can do in a few minutes and without cost.

If this test shows an excess of sand, add compost or other organic material to improve the mix. During January or February, you could lift the rose, dig a hole about twice the size of the root ball, fill the hole with a mixture of garden soil, sand and compost, replant the rose, and water in. There is no correct mixture, but you might try for something like 70% soil, 20% sand and 10% organic material.

When lifting the rose, first use a shovel to cut the roots to about six inches around the plant. You could lift the plant without soil around the roots, but keep the roots moist (or at least out of the sun) until replanting.

A foggy environment has good and bad effects. Fog will help to keep the rose from drying out, but it will also promote various diseases, e.g., mildew, black spot, rust. The best strategy lis to select disease-resistant roses. Here’s a link to a Sunset magazine article, “Roses for Foggy Coasts,” with a list of rose recommendations.

The article recommends seeking advice from members of the local rose society. The Monterey Bay Rose Society has several members who are qualified Consulting Rosarians, and generous with their expertise.

Lose the Lawn

One the best gardening strategies to prepare for future droughts—and achieve additional benefits—is to replace your lawn with any of several landscape designs.

Lawns, and especially front yard lawns, began as a mark of affluence, because mowing a lawn was once a labor-intensive (and therefore costly) session with a scythe. A skilled scythe-wielding worker can be impressively efficient, but for most workers, including the homeowner with an up-to-date lawnmower, mowing a lawn is a tedious and repetitious task. The homeowner’s reward for a well-maintained lawn can include pride of ownership.

A lawn does more than display the homeowner’s wealth. It also serves as the base for widely accepted front-yard designs, the principal one of which has been called the Contractor’s Landscape. This consists of a shallow bed of reliable small shrubs next to the house, followed by turf grass to the curb. This design is quick and cheap to install, and inoffensive.

From an aesthetic viewpoint, the lawn provides a resting place for the eye as the viewer focuses on individual trees, shrubs and blossoms. The lawn is a neutral swatch of greenery, contrasting carpet-like with the relatively busy landscape.

But consider the negative aspects of the lawn.

  • Maintaining a good-looking lawn requires much more effort, water, chemical fertilizers and herbicides than alternative landscapes.
  • Two-cycle lawnmowers pollute the air about ten times as much as a car, and add noise pollution as well. Electric mowers are better, but they also impact the environment. Push mowers are best for the environment, the lawn and the homeowner.
  • Lawns are the homeowner’s version of monoculture, growing just one crop over an area. This practice might seem efficient, but to the wildlife, it’s a wasteland with very little food or water and no shelter at all.
  • Lawns might be valued for recreation, but in reality often have minimal use (except for maintenance). Other landscape designs could be more inviting and supportive of outdoor activities.

If these factors encourage you to consider losing your lawn, it’s time to look into the many possible alternatives. Begin with Sunset magazine’s “21 Inspiring Lawn-free Yards” <>. This webpage offers a slideshow of attractive options to contemplate.

For more in-depth information, visit Evelyn J. Hadden’s extensive website, “Less Lawn, More Life,” or look for her book, “Beautiful No-Mow Lawns: 50 Amazing Lawn Alternatives’ (Timber Press, 2012).

Another fine resource on this topic is book by Carol Bornstein, David Fross and Bart O’Brien: Reimagining the California Lawn: Water-conserving Plants, Practices andDesigns (

Another helpful resource is the Lawn Reform Coalition, which is “all about reducing or replacing lawn, water-wise lawn species and eco-friendly care for all lawns.” Visit the Coalition’s website for information on all aspects of lawn alternatives.

“Lose the lawn” emphasizes the loss of a familiar element of the landscape. “Lawn alternatives” suggests a more appealing idea, one that opens our thinking about creative approaches to the landscape and new resources in the home environment.

Think of the possibilities!