Talking About Gardening

A popular activity whenever gardeners get together is for someone to give a talk. This links the speaker’s desire to share what he or she knows about gardening and the listener’s thirst for learning something—anything—about the enduring mysteries of horticulture.

Often, there are pictures.

When a speaker addresses the methods, techniques, or practices of an aspect of gardening, the presentation amounts to teaching. When teaching equals performance in the front of the room, good teaching (according to some studies) requires the teacher to have knowledge of the subject, have a positive attitude toward the subject, and to be prepared.

The same basic criteria apply to talks about gardening.

Being prepared, in particular, means having specific goals for the talk, organizing the information for clarity, and providing a level of detail that is right for the audience.

More is needed, however, for the talk to be successful. The additional criteria apply mostly to the method of the presentation:

  • Speak loudly enough for everyone to hear
  • Make eye contact with audience members
  • Listen to questions from audience members (and observe their body language)
  • Restate and respond to individual questions so the full audience can hear
  • Know when to stop

The Internet contains more ideas for effective public speaking. Many recommendations are about the style of presentation, e.g., incorporating humor, adding personal anecdotes, pausing occasionally for dramatic effect, etc.

With many familiar recommendations like those listed here, we might expect generally successful talks about gardening, but really good presentations are actually exceptional.

A recent presentation for the Monterey Bay Area Cactus & Succulent Society exemplified a good talk on gardening. The speaker was Gunnar Eisel, a long-time college professor of music theory and history, a long-time collector of cactus & succulent plants, and general manager of the Cactus & Succulent Society of America.

His experience in public speaking was made evident when he appeared fully equipped with his own computer, digital projector and a sound system of very good quality. Clearly, he had one too many encounters with inadequate technology provided by his hosts.

Gunnar Eisel titled his talk, “From Windowsill to the Poor House: Building and Maintaining a Cactus and Succulent Garden.” He organized his information in sections: Why Collect?; Kinds of Collections; Sources of Plants; Right-sizing Your Collection; Visual Tours of Selected Collections; and Culture Recommendations.

His presentation reflected his deep knowledge of and enthusiasm for his subject, and maintained the rapt attention of his audience for about one hour with good pacing, well-selected images and short video clips, and friendly humor.

Once you’ve enjoyed a really good talk on gardening, it’s tempting to be rough on speakers with less expertise, but this talk has inspired the Society to develop a tip sheet for its future speakers on gardening topics. That is work in progress. Sources of potentially useful ideas include the website for Great Garden Speakers, which provides links to gardening experts, and Jeff Haden’s “20 Public Speaking Tips of the Best TED Talks.”

Not every garden group is prepared to bring in outstanding speakers, but expert gardeners who share their expertise with others can refine their presentation skills.

A Primer on Succulent Plants

California’s recent drought, which promises to stick around in future years, has inspired a surge of interest in succulent plants, which, as a group, grow nicely with limited moisture. If you already know all you want to know about succulent plants, you can skip this column, but if (like many gardeners) are just becoming interested in such plants, here is a primer.

Gardeners who explore the world of succulent plants soon discover that these plants have more to offer than drought tolerance:

  • They bring a great range of forms, foliage colors, blossom colors, and sizes
  • Some grow well in bright sun, while others thrive in filtered light
  • There are are winter dormant varieties (“summer bloomers”), and summer dormant varieties (“winter bloomers”).

These characteristics make succulent plants terrific for landscaping and container gardening.

Cream Spike Agave

Cream Spike Agave, from Mexico

Cream Spike Agave - cu

A closer look

The world of succulents includes some ambiguities to get used to, as follows:

First, the term “succulent” refers to the plant’s biological ability to store water during dry spells, and does not indicate a botanical category. The succulent characteristic occurs within about sixty different plant families. Succulence is a variable trait: succulent plants differ in their needs for moisture.

Second, some definitions of succulent plants exclude geophytes, which are plants that store water underground structures called bulbs, pseudobulbs, tubers, corms, rhizomes or other terms. Interestingly, plants that store water in a caudex (a modified stem that might be partially underground) are considered succulents even when geophytes are not.

Third, all cactuses are succulents, but all succulents are not cactuses. Cactuses are in the plant family Cactaceae. All plants in this family have specialized structures called areoles, a kind of highly reduced branch that produces spines, which are highly modified leaves.

Fourth, except for the cacti, succulent plants do not have spines, but some have leaves with hazardous sharp points or spiked edges, intended to discourage predators.

Always the best way to learn about plants is to grow them. Hands-on experience and regular observation are the best forms of education.

There are faster ways, however. The Internet contains vast informational resources about succulents, accessible by searching on any plant name or botanical term in this column. Very helpful Internet resources for this purpose include Wikipedia for botanical information, Pinterest for photos of succulent plants, and YouTube for video clips on all aspects of growing and displaying succulent plants.

Another very good strategy, especially for Monterey Bay area gardeners, is to join the Monterey Bay Area Cactus & Succulent Society (http://mbsucculent.org/). This non-profit group has monthly meetings in Watsonville, with expert presentations, a fine lending library (listed on its website), and public shows and sales in the spring and fall. The shows at these events include displays of a great variety of expertly grown and often extraordinary succulent plants. The sales present a vast number of small and not-so-small plants in great variety and for attractive prices.

If You Go

What: Spring Show & Sale of Cacti and Succulents

Who: Monterey Bay Area Cactus and Succulent Society

When: Saturday, April 23, 9:00 to 5:00 and Sunday, April 24, 9:00 to 4:00

Where: Community Hall, 100 San Jose Avenue, San Juan Batista, California

Admission and Parking: Free for all visitors

Drama for the Landscape

 

One of the most spectacular plants from South Africa, in exuberant bloom at this time of the year, is Aloe arborescens. It can be seen throughout the Monterey Bay area, occasionally having spread into impressively large clusters of plants.

The specific name means “tree-like,” because the plant can grow to close to ten feet high. Structurally, the plant consists of several branches, each of which ends in a rosette of leaves edged with small spikes. Each rosette can generate several flower stalks that produce cylindrical inflorescences (racemes). The individual flowers, typically a bright orange-red, are tubular and attractive to hummingbirds. The clusters of flowers resemble the flame of a torch, leading to the plant’s common name: Torch Aloe.

DSCF0022 DSCF0023 DSCF0024 DSCF0025

Several years ago, I planted my first specimen of this succulent plant, a single rosette, in a well-drained bed. It grew rapidly and extended runners (stolons) that produced new plants, ready to take over the bed. Not knowing its full growth potential, but realizing that it was too productive for that small bed, I shovel-pruned it, replanted three rosettes in front of a nearby compost bin, and placed most of the rest in the bin.

The replanted rosettes grew readily into a dramatic presence in my garden, and also shielded the compost bin from view.

A. arborescens is related to A. vera, a smaller, more familiar South African native that is popular for its ornamental, cosmetic and medicinal values: its juices reportedly have rejuvenating, healing, or soothing properties.

The Torch Aloe also reportedly has value in promoting good health. Some people advocate a drink made from the pureed whole raw A. arborescens leaf, unheated raw honey and 1% certified organic alcohol. This drink is claimed to support immunity from a range of diseases and provide general cleansing for the whole body. It is reported to be “bitter, but unctuous and savoury as well, thanks to the honey.”

I have plenty of leaves but have not tried the drink. This is not a testimonial.

A. arborescens is one of about 500 species of the genus Aloe, which includes natives of South Africa, tropical Africa, Madagascar, Jordan, the Arabian Peninsula and some islands in the Indian Ocean. Many grow well in the summer-dry climate of the Monterey Bay area. Most species, unlike A. arborescens, are stemless: the rosettes grow directly on the ground.

A smaller, yellow-flowered variant, called Golden Torch Aloe (A. arborescens lutea), can be found in limited numbers.

Another yellow-flowered form, Yellow Aloe, was discovered in a private garden in Santa Barbara. This plant might be a variant of A. arborescens, a hybrid with another species, or an entirely different species: A. mutabilis, which has red flower buds that mature into yellow.

Aloe arborescens can be an attractive and interesting addition to a landscape that has sufficient space.

Rethinking a Planting Bed

There are a few reasons for a gardener to re-think a planting bed: inspiration for a new approach, boredom with the old approach, overgrown plants (and an invasion of weeds), or a desire to improve the aesthetics.

For one of the beds in my garden, I have the urge to edit the existing plants to satisfy to a thematic concept: Mexican Succulents.

At least ten years ago, I established this bed, which is not large (almost forty square feet) but prominently located in the garden. An edge of larger stones supports a raised planting area, which is ideal for succulent plants. Over time, I installed a variety of succulent plants.

When I look at this bed now, the mix of plants leaves me uneasy. During the intervening years, I have become interested in thematic collections of plants, with an emphasis on county of origin. From that perspective, this bed was a horticultural hodge-podge.

For some gardeners, that reaction might suggest an unhealthy obsession with order, but that’s OK. It’s my garden and I can do what I want.

This concern, which has been lurking in the background for a while, was activated recently by two events. First, at a meeting of the Monterey Bay Area Cactus & Succulent Society, I attended a presentation on Agaves, a southern California succulent. Then, a friend gave me an Agave parryi (Mescal Agave), which is also from southern California and northern Mexico.

I already knew most of the plants in this bed were Mexican or southern Californian, the featured plant being a Dasylirion wheeleri, also called a Desert Spoon.

Dasylirion wheeleri

Dasylirion wheeleri, a succulent plant from Mexico, with a large South African succulent, an Aloe arborescens, in the upper left background.

My concept of “Mexican Succulents” includes southern California, because plants don’t recognize political boundaries, and besides, historically, Mexico included what we now know as southern California.

My first step toward that objective was to inventory the existing plants, to determine which should be relocated. I identified plants from South Africa: Crassula tetragona (Miniature pine Tree), Crassula argentea (Jade Plant), and an enormous Aloe arborescens (Torch Aloe), which has been screening my compost bins.

I also found plants from the Europe and the Mediterranean basin: a self-seeding Euphorbia characias wulfenii (Mediterranean Spurge), a few unidentified plants: Sedums, Sempervivum, and Aeonium.

The task, then, is to move the South African succulents to another bed that already has that theme and to move the others to the bed for Mediterranean Basin plants. The biggest challenge will be to remove the South African Torch Aloe, which needs a larger space than is available elsewhere in the garden, and to find another screen for the compost bins. Aloes are hard to kill, so I could give away cuttings at the curb for other gardeners.

Then, I could assess the newly dedicated bed for Mexican Succulents and begin filling in the empty spaces with new plants, beginning with my one Agave parryi. I probably will avoid collecting agaves because they have sharp terminal spines, are monocarpic (they die after flowering), and produce lots of offsets (pups). There are many other Mexican succulents to explore.

A good practice is to tour your garden occasionally to consider if a bed could be improved by editing the plants, or starting over entirely. It’s best to focus on a limited area, rather than taking on the entire garden at one time. Renewing a planting bed should be a creative exercise and could lead you into a new area of gardening.

Adventuresome Gardening

Regular readers of this column know of my interest in plants from the world’s summer-dry climates, also called the Mediterranean Basin regions. Many plants from these exotic regions will thrive in the Monterey Bay area, and provide attractive and exciting alternatives to the garden center’s humdrum horticulture. Cultivating such plants is the enterprise of adventuresome gardeners and seekers of botanical thrills.

There are countless examples of such plants to be discovered among the selections of mail-order nurseries, either in published catalogs or online. To be fair, local garden centers also might have a few offbeat offerings; it’s worth asking the staff to mention any unusual plants.

One candidate for a featured position in the landscape is the Puya, which is one of about fifty-seven genera in the Bromeliad family. Just about all bromeliads are native to the tropical Americas. About half of the species are epiphytes (growing on air and rain), some are lithophytes (growing on rocks), and the rest are terrestrial (growing on earth). The most familiar of the terrestrial bromeliads is the pineapple (Ananas comosus).

Another terrestrial bromeliad is the Puya. This genus includes about 210 species, several of which are native to Chile, where they have the common name chagual.

One of the Chilean Puyas is the Blue (or Turquoise) Puya (P. berteroniana). This plant grows a flower spike about six-to-ten feet tall, and has exceptional landscape value because of its extraordinary 1.5” waxy, metallic blooms of an unearthly emerald-turquoise color, with contrasting bright orange stamens. The blooms hold blue, syrupy nectar that attracts hummingbirds, bees and other pollinators.

Puya berteronianas

The Blue Puya can be found in some public gardens. I viewed several fine specimens, and took this photo, about one year ago, in the Australian National Botanic Gardens, in Canberra.

Locally, the Blue Puya is in bloom now at the UCSC Arboretum. The blooms do not last long, so to see one of nature’s most extraordinary flowers, visit the UCSC Arboretum soon. For information and pictures, visit arboretum.ucsc.edu/ and click on “What’s Blooming.”

The Chilean bed in my garden includes two quite young examples of this genus: a Blue Puya (P. berteroniana) and a Silver Puya (P. coerulea). These are slow-growing plants, now years away from blossoming in my garden. While they are not yet pleasing my eyes, they are already trying my patience (a little) and piquing my imagination.

Annie’s Annuals lists nine Puya species, but current availability includes just three. Similarly, the wholesale nursery San Marcos Growers lists eight Puya species, with just three currently in production. Your local garden center could special-order plants from these nurseries, or another preferred source. Search the Internet by botanical name for information to share with garden visitors.

You certainly can keep your garden’s tried and true selections, but consider adding exotic plants to enrich your landscape.

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 wikipedia.org.

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.

The Ageless Aeonium

Today, we introduce the genus Aeonium, which includes 35 species, most of which are from the Canary Islands, northeast of Africa.

These plants are characterized by the development of rosettes of leaves on basal stems, i.e., stems that rise from the plant’s roots.

The generic name, Aeonium, comes from an ancient Greek word that means “ageless.” In fact, for most species, the rosettes die after producing a flower, although the entire plant lives. A few species are monocarpic, meaning that they produce a single rosette without a stem, and then the entire plant dies.

Popular Cultivars

  1. A. ‘Zwartcop’ (Black Rose), a cultivar of A. arboretum, develops rosettes with very dark reddish-purple, almost black leaves, on stems that can rise to four feet. This plant produces effective displays in the landscape or in a mixed container, especially when contrasted with yellow flowers like those of the plant’s own blossoms.
  2. A. ‘Sunburst’ (Copper Pinwheel), a cultivar of A. davidbramwellii, is a variegated form, with large rosettes with variegated green and white leaves edged in bright, coppery red. The stalks rise up to 18 inches. ‘Sunburst’, like other variegated plants, can provide pleasing contrast in the garden.

Aeonium 'Sunburst' best

  1. 3. A. nobile (Noble Aeonium) produces a single, stemless rosette up to nearly two feet in diameter, making it entirely distinctive among the aeoniums. The leaves are yellowish, with a reddish edge when grown in bright light. This is one of the monocarpic aeoniums: it dies after producing its reddish blossoms.
  2. A. tabuliforme (Saucer Plant, Dinner Plate Plant) is another monocarpic aeonium that provides a single, unique, nearly flat stemless rosette.

Cultivation

Aeoniums will be dormant during the summer months and resume growing in the early autumn.

They are very easy to grow in containers, where they flourish with their shallow roots and occasional watering. Use a normal potting soil, rather than a fast-draining cactus mix. In the Monterey Bay area, they prefer bright morning sun and afternoon shade. Fertilize only when the leaves become yellowish, indicating nitrogen deficiency. Too much fertilizer will promote too-rapid growth and weak stems.

When grown in the garden in this area, aeoniums require little care. As with container plants, avoid very rich soil and fertilizers.

Propagation

All aeonium species and hybrids can be propagated from seeds, but most are propagated easily from stem cuttings. This might be done to produce additional plants or to bring a rangy plant into a more compact form. During the plant’s normal growth period, from autumn to mid-spring, cut a rosette with up to five inches of stem (shorter for smaller, shrub-like forms) and place in a cool shady place for at least three days, to heal over. Then, place the cutting in a normal potting mix, in a small container, and in a shaded, windless location to reduce moisture loss. After the plant has established roots, place in a container or in the garden.

The monocarpic species are not propagated from stem cuttings, but from leaf cuttings, which are more successful with A. tabuliforme than with A. nobilis.

Aeoniums are drought-tolerant plants that are easy to cultivate and interesting additions to the garden.

Water Storage Tricks

With our persistent drought, and the possibility that it signals a long-term change in our climate, gardeners are becoming interested in succulent plants. They warrant a closer look.

All plants store moisture in various parts of their anatomy. Succulent plants store more moisture than plants in general, having adapted to surviving in areas of irregular rainfall.

Succulence is a characteristic of plants, rather than a taxonomic category. As a result, identifying succulent plants can be an arbitrary exercise. For example, some gardeners will group succulents apart from geophytes and cacti, although both store moisture. That’s OK, because “succulent” is not a formal definition, but it’s still appropriate to think of geophytes and cacti as good at storing moisture.

Succulents are found in about sixty plant families, and a wide range of genera within those families.

One unusual group of succulent plant is the caudiciforms, which store moisture in a caudex, which is a woody stem structure that typically develops just under the surface of the soil. Gardeners who enjoy growing these caudiciforms in containers often adjust them to display the caudex above (or partially above) the soil surface. The caudex, also called a “lignotuber,” is not attractive in the conventional sense, but by any name it is an ingenious adaptation of the plant to unreliable moisture conditions.

My garden includes two caudiciform plants. One is a Ponytail Palm (Beaucarnea recurvate), from Mexico, which is not really a palm. The cultivation advice for this plant is to never water. This might seem harsh, especially for gardeners who equate watering regularly with nurturing the plant, but it indicates that the plant is epiphytic, meaning that it derives moisture and nutrients from the air, rain, and sometimes from debris that accumulates around it.

Ponytail Palm

Ponytail Palm (Beaucarnea recurvate). Click to enlarge the photo, and make more visible the caudex at the base of the plant.

Screen Shot 2015-08-02 at 8.30.44 PMMy other caudiciform plant is a Beautiful Serpent (Agapetes serpens), which is from the Himalayan mountain range north of India. It is in the Ericaceae (Heath) family. The plant’s specific name refers to the snaky growth of its stems, but its blossoms are more distinctive, in my view.

 

I have not seen the common name, Beautiful Serpent, online, but that’s what I call this plant.

Screen Shot 2015-08-02 at 8.31.19 PMMy plant is A. ‘Ludgvan Cross’, which is a cross of A. serpens and A. rugosa, both from the Himalayas. This hybrid has distinctive chevron markings on the blossoms.

 

Both photos of Agapetes serpens are from Strange Wonderful Things: Rare and Exotic Plants which is a fine website for gardeners to visit.

I found this rather rare (or at least uncommon) plant in a local garden center, then found online cultivation advice that emphasized bright but cool conditions, with protection from the afternoon sun. This seemed appropriate for a plant from the Himalayas, so I put in a container of about 1.5-gallon size, filled with good potting soil, placed the pot in a bright shade location, and watered it regularly.

The plant grew well enough, but has produced few stems and blossoms, compared to photos I have seen online. It didn’t seem happy.

With a bit more research, I learned for the first time that this plant is a caudiciform. The caudex is below soil level, so this was a surprise. Then with further research, I learned that it is also epiphytic! This is a game-changer.

Not all caudiciform plants are epiphytic, but they use available moisture very efficiently, so irrigation should at least be limited.

My cultivation plan for this plant now involves keeping it in the same bright shade location, and discontinuing irrigation. Reportedly, it prefers humid conditions, so I might mist it occasionally.

The first takeaway from my experience with this plant is to find more than one source of information on unusual plants that you bring to your garden. The Internet holds an amazing wealth of information of value to gardeners, and we should draw upon it routinely.

An important first step in researching a plant is to learn its botanical name. A search based on a common name often will lead to good information, but the botanical name is more accurate and preferable.

Try one or more caudiciform plants among the succulents in your garden. A rich source of information on these plants is the website bihrmann.com. Hint: when you browse to the home page, click on the image immediately after “.com.”

Incidentally, you might enjoy exploring this website, which has many images of flora and fauna, in several categories. The author, identified only as Bihrmann, has travelled extensively, taken an enormous number of photographs and lived a rich life. Some of the pages are in Danish.

***

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 gardening.com 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
JACQUELINE RAMSEYER —
BAY AREA NEWS GROUP

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.

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.