In the garden, one thing always seems to lead to another.

I began by thinning one plant that had begun to crowd a bed in my garden. The plant is the Rain Lily (Zephyranthes candida), a low-growing bulb in the Amaryllis family, native to South America. It has grassy foliage, evergreen in the Monterey Bay area, and six-petal blossoms, white with a pink wash. (Pink blossoms are more common in the genus.)

After a few seasons in the ground, the Rain Lily generates many small bulbs and spreads happily. My original one-gallon clump expanded to fill nearly half of a semi-circular bed about thirty-feet in diameter.

I gathered hundreds of bulbs to share on June 23rd through the Garden Exchange at The Garden Faire (thegardenfaire.org).

That project created open space in that prominent front yard bed, and the opportunity to rethink its design. A rock garden seemed an obvious choice: the bed is already mounded and has a few largish boulders.

My preliminary inquiries into rock garden design revealed that this bed doesn’t qualify as a rock garden, but is instead a “rockery.” A rock garden has particular soil, rocks, and plants; a rockery is simply any planting bed with decorative rocks.

Serious rock gardeners study instances in which plants grow in a rocky environment. This occurs typically in a mountainous region, which will have high elevation, rocky ledges on sloping sites, rock outcroppings on more level land, and crevices, which are narrow, soil-filled spaces between rocks. The soil in such regions typically will be poor in nutrients and fast to drain. The climate usually will be windy and marked by much sun exposure.

The plants in a natural rock garden will have evolved to survive in those relatively hard conditions. The classic rock garden plants are called “alpines,” meaning plants that grow in The Alps, one of the great mountain range systems of Europe. These plants could be herbaceous or woody, and grow up to about one foot high.

Another category of rock garden plants includes small rock (“saxatile”) plants, which grow in rocky sites at lower elevations. These plants are easier than alpines to grow in most residential gardens because the gardener doesn’t need to recreate the uncommon conditions of a mountainous environment.

A popular feature for rock gardens is the scree bed, an area of loose rocks and stones that might occur at the bottom of a slope, perhaps deposited there by a landslide. A larger rock garden might have a sand bed, an acid heath bed, an “alpine meadow, or a boggy area beside a pond or stream.

A rock garden could succeed in a small setting as well, making this interesting naturalistic design concept adaptable for placement in gardens of all sizes.

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A small rock garden could be created in a container. An appropriate container would be a hypertufa trough, which you can build yourself. Here are instructions from Fine Gardening magazine.

If you have larger project in mind, take the time to research the basic concepts, to be sure you are on the right track and won’t end up with a rockery instead of a rock garden. There are good books on the subject. Here are three that are available on Amazon.com:

Rock Garden Design and Construction, by North American Rock Garden Society (2003)

The Serious Gardener: Rock Gardens (New York Botanical Gardens), by Ann Halpin and Robert Bartomonei (1997)

The Rock Garden Plant Primer: Easy, Small Plants for Containers, Patios, and the Open Garden, by C. Gray-Wilson (2009)

Many gardens begin as level rectangles, with a residence more or less in the middle. It doesn’t have to be that way.

If your garden has natural changes of elevation or an irregularly shaped boundary, or both, you could have an interesting context for your garden design.

Dramatic departures from the level of course could be more challenging than inspiring. Workers on steeply sloped vineyards in Germany’s Rhine Valley hold on long ropes to keep from tumbling into the water.

Likewise, an oddly shaped plot could be more trouble than help. Municipal regulations generally prohibit building on small parcels of very unusual form, but such a parcel could accommodate a community garden.

If your garden amounts to a level rectangle, and consequently lacks interest, consider your options for creating elevation changes.

Below-grade elevation change possibilities include a swimming pool, a naturalistic pond, a bog garden (more shallow than a pond) and a rain garden (which collects rainwater and lets it seep into the ground). A swimming pool is mostly a recreational resource, but the other three offer interesting gardening possibilities.

For very large parcels, another below-grade option is the ha-ha. This is a ditch between a garden and a natural area, intended to keep domestic or wild livestock from straying into the garden. The ha-ha typically runs across the line from the residence to the natural area in the distance.

Above-grade elevation changes include raised beds, berms, terraces and sculpted landscapes.

Raised beds are usually rectangular, rising only a few inches above grade, primarily to improve drainage. They could be simple low mounds or might have low walls of wood or other materials. A raised bed also could be about table height, to raise the planting surface for the gardener’s convenience. Such beds are sometimes made for accessible gardening by gardeners with physical limitations.

Berms are like large raised beds. They generally are eighteen to twenty-four inches high, curved for a natural look, four or five times as long as wide, and with sloping sides. They could provide higher quality soil (imported), superior drainage, or just visual interest.

For a short article on creating and using berms in the landscape, click here.

Terraces are similar to steps, and, like steps, provide one or more level areas to ease the transition from one elevation to another. They also have aesthetic value when well designed, and can improve the visibility of ornamental plants.

To view an unusual example of a terraced landscape (a rice field in China), click here.

Sculpted landscapes, above- or below-grade, are typically large-scale imaginative earthen constructions intended primarily for visual interest.

A fine example of a sculpted landscape can be seen at the WiIlliam J. Clinton Presidential Center (click here).

These possible elements of the landscape are not difficult or very expensive to accomplish, and could transform a flat rectangular garden into an interesting landscape. They also offer a fine opportunity for creativity in garden design, complementing the core activities of plant selection and placement.

Enjoy your garden!

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One of gardening’s countless sayings is that all gardens are works in progress. That is true of my own garden. Long-time readers of this column will recall that I have been developing a drought-tolerant garden with beds representing the world’s five major dry-summer regions: the Mediterranean basin, South Africa, Chile’s central coast, southwestern coast of Australia, and California’s coast.

This project involves converting an existing a nondescript landscape into a thematic garden. In addition to the five summer-dry regions, the garden includes beds devoted to roses, irises and salvias.

Despite the progressive nature of gardening, there are occasional moments to celebrate reaching certain accomplishments. After many weekends of diligent work, I can report that my helpers and I have cleared a daunting accumulation of weeds, upgraded the irrigation controllers and valves, installed drip tubing and emitters, and mulched every square foot of bare soil.

During this time-consuming process, several good plants died. Hand watering has never been my strong suit!

We have the continuing adventure of finding plants from these far-flung regions, putting them in the ground, and documenting the collections with paper records and plot diagrams.

This approach to landscaping has yielded two important realizations. First, collecting plants by dry-summer region tends to abandon all but very basic design concepts. By definition, all dry-summer plants are suitable candidates for the Monterey Bay climate. Also, the gardener can still select and place plants that have mature sizes that are right for the space. Finally, the gardener can still position the smaller plants in front and the larger plants in back.

The finer points of landscape design generally are beyond reach. This garden does not include subtly artful contrasts of leaf textures; complementary, analogous or triadic combinations of blossom colors; or a year-round schedule of blooms. It also does not include plant communities (clusters of plants that grow together in nature). Instead, each bed offers an essentially random collection of plants from a climatic region, some of which seem puzzled by their strange bedfellows.

In my view, it is interesting nevertheless.

As I gradually convert the garden to a “botanical zoo,” I have to decide the fate of plants that were included in the previous landscape but do not belong in the new landscape. I could just relocate smaller plants. Most Monterey Bay area gardens already include plants from dry-summer climates because they are good choices for the local climate.

Larger shrubs and trees are another story. I have callously removed some smaller trees, donated two huge salvias to a friend who maintains a more spacious garden, and given away many smaller perennials. Currently, I am agonizing over a thirty-foot elderberry (Sambucus cerulea?) that is shading the Australian garden.

Enjoy your own work in progress!

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Here are photos of the elderberry tree in the Australian garden, and a Blue Hibiscus, one of the plants that isn’t getting all the hours of sun that they prefer.

At this time of the year, gardeners often become bemused by blossoms, which beautify our gardens, garden centers and garden magazines. The seasonal burst of colorful petals surely ranks among the finest rewards of gardening.

These flowers, however delightful visually and olfactorily (if that is a word), can tempt us to overlook another important element of the landscape: foliage.

One of history’s great gardeners, Christopher Lloyd, wrote, “Certain groups of plants have particularly dull and dreary foliage and depend 100 percent on their flowers to disguise the fact.” There are many examples: the entire very large Daisy family (the Compositae), dahlias, chrysanthemums, and many more.

“Dull and dreary” is a matter of opinion, of course, and Lloyd was never reticent in expressing his opinions, but when we contrast “ordinary” foliage with the alternatives we discover that the leaves of plants offer great variety and appeal, rivaling that of the flowers.

Foliage has been categorized often, with varying degrees of success. Leaves occur in so many subtly different ways that grouping them succeeds only if we accept compromises.

With that caution, foliage has been described principally in terms of two important variables: color and texture.

The principal foliage color group is green. The briefest survey of a plant collection reveals that green leaves come in many different hues of green.

Other major color groups include gold (yellow, bronze, brown, etc.); dark colors (red, purple, black); the silver, gray and blue cluster, and multicolored leaves.

Texture, the other important variable, might refer to the overall size of the leaf: bold or large, medium, fine, or lacy.

Texture might refer to leaf shape: spiky or sword-shaped, round, oval, palmate, and many other shapes.

Texture might also refer to leaf surface, which could be glossy, dull or fuzzy, smooth or crinkled. A complete description of any given leaf involves multiple characteristics that botanists have defined and that the home gardener can safely reduce to a favored few.

For the gardener, the many colors and textures of foliage represent opportunities for adding interest and beauty to landscapes, container gardens and floral arrangements.

Books and articles on gardening and floral arrangements often feature combinations that the writer finds particularly appealing. Given the variability of both flowers and foliage, an immense number of good combinations could be described. Ultimately, the best combinations reflect individual preferences.

The gardener’s practical approach to designing an aesthetically pleasing combination of flowers and foliage involves study available plants, and imagining them together with a creative eye. This also involves moving potted plants around, to see them beside potential companions. This strategy works best in garden centers, where all plants are movable.

More about foliage plants and ideas for their many uses:

Look for these books in your local bookstore or library, or search online.

The Foliage Garden: Creating Beauty Beyond Bloom, written by Angela Overy, with photographs by Rob Proctor (Harmony Books, 1993).

This book is full of good ideas for the garden. It’s a welcome alternative to the many books that lists descriptions of plants within the author’s category of interest.

Foliage, written by Harold Feinstein (Bulfinch Press/Little, Brown and Company, 2001).

A “coffee table” book of dramatic full-page photographs of foliage, with plain black backgrounds, plus brief essays by the author and contributors, introducing a series of topical photos.

Foliage: Astonishing Color and Texture Beyond Flowers, written by Nancy J. Ondra, with photographs by Rob Cardillo.

This book provides the familiar list of plant descriptions within a category. In this case, sub-categories organize foliage plants in three color groups (gold; red to black; and silver, gray and blue) plus “Marvelous Multicolors.” This approach is quite helpful to the gardener in planning a bed.

Foliage Plants, written by Christopher Lloyd (Random House, 1985)

Christopher Lloyd (d. 2006), creator of the highly regarded estate garden, “Great Dixter,” (today, a popular public garden), was one of gardening’s gurus and a prolific writer of authoritative books on many aspects of gardening. His sharp opinions, generously offered, make reading his books amusing as well as instructive.

I am just now reading this book, so I will refer interested persons to a brief review on the website, Good Reads.