Low-Maintenance Garden Themes

Designing a garden bed around a theme yields practical and aesthetic benefits.

The aesthetic benefit of thematic garden design rests on the relationships among the plants: they are linked by being members of the class defined by the theme. In that respect, a thematic group is more coherent, aesthetically, than the ever-popular “grab-bag” approach to plant selection.

The practical benefit is a plan for selecting plants from the hundreds of thousands of available varieties. Once the gardener has chosen a theme, he or she has reduced the universe of possible plants to consider. This one action narrows the selection task and supports close evaluation of options.

A garden design theme is simply a concept to which plants relate. This definition embraces a very wide range of possible themes, which could be a single color or combination of blossom colors; a plant genus, e.g., rose, iris, daffodil; size, e.g., miniatures; bee-friendly, etc.

For today’s topic, consider a progression of four themes for low-maintenance gardening.

Theme #1: Zone-appropriate Plants. Every gardener should know the U.S. Department of Agriculture’s Plant Hardiness Zone in which his or her garden exists. The Monterey Bay area is in USDA Zone 9b, where minimum temperatures are in the 25–30 degree range; plants marked for Zone 9 should survive cold spells in that range. A great many plants are that hardy, so this theme excludes only plants that are vulnerable to cold and therefore high-maintenance. Nurseries also use UCDA zones to indicate the preferred zone for given plants. Plants that are rated for Zones 10 or 11 usually will thrive best in very warm climates, not in Zone 9.

Theme #2: Mediterranean Climate Plants. These are plants that have evolved to grow well in the world’s areas that have dry summers and moderate winters. These areas (again) are native to the central coast of California, the central coast of Chile, the southwestern coast of Australia, South Africa and the Mediterranean basin. A large number of plants are suitable for this theme, but this category still is significantly smaller that Theme #1.

Theme #3: California Native Plants. This theme is within Theme #2, of course, but it stands apart from the others because includes plants that are both suitable for the Mediterranean climate and the soils and fauna of this state. Soil chemistry and symbiotic relationships with birds, mammals, insects and microbial life contribute significantly to the growth of plants, and, ultimately, the success of the gardener.

Theme #4: Native Plant Communities. A great variety of plants are native to California, and many have evolved to grow best in specific environments within the state, and in communities with specific other plants. An oak woodland plant community is certainly different from one that occurs naturally on coastal bluffs and cliffs. For the ultimate in low-maintenance gardening, adopt a thematic design for a California native plant community that would be appropriate for your garden setting.

Consider a thematic design for each garden bed or each large area of your garden. Plant selection will transform a random process to a purposeful activity.

Books for Thematic Designs

Zone-appropriate Plants
The New Western Garden Book (Sunset, 2012)

Mediterranean Plants
Plant Life in the World’s Mediterranean Climates (Dalman & Ornduff, 1998)

California Native Plants
California Native Plants for the Garden (Bornstein, Fross & O’Brien, 2005)

Native Plant Communities
Designing California Native Gardens: The Plant Community Approach to Artful, Ecological Gardens (Keator, Middlebrook & Faber, 2007)

 

Gardening with Exotics

Many of the plants we enjoy in our gardens produce flowers. We also enjoy many plants for their foliage, but the flowering plants, called angiosperms, are the ones that attract our attention.

The angiosperms, which first developed about 245 million years ago, have grown to dominate the terrestrial ecosystems, exceeded only by the coniferous forests.

There are about 260,000 species of angiosperms, and the growers of the most popular garden species have produced countless selections, hybrids and cultivars. When we visit our local garden centers or flip through catalogs of mail order plants, we see most often those variations of the most familiar plants.

Some avid gardeners eagerly seek the latest introductions of roses, irises, petunias and other and take pleasure in being among the first in their communities to have the hybridizers’ newest achievements. Each year, when we might think that new versions of popular plants are not possible, we find unexpected colors, new color combinations, more vigorous or more floriferous producers, and plants that have been bred to be more resistant to pests and diseases.

These new introductions are often the most costly plants offered, reflecting both their appeal to consumers and the costs of development and introduction. The most enthusiastic collectors of the best and latest do not flinch and gladly pay the premium prices.

Gardeners who appreciate unfamiliar and interesting plants have alternatives to each year’s new crop of high-priced new introductions. The vast array of angiosperms includes many exotic, garden-worthy plants with gorgeous blossoms that are rarely seen in garden centers or catalogs, and are very much worth the time and attention of gardeners.

The local gardener’s search for exotic flowers will be most successful when focused on plants that are well suited for the special growing conditions of the Monterey Bay area. These include plants from the world’s “summer-dry” climate regions, including coastal California, the central coast of Chile, the southwestern coast of Australia, South Africa and of course the Mediterranean basin.

A wide selection of interesting plants is native to these areas, and will succeed in the Monterey Bay area with routine care.

One example of an interesting exotic from a summer-dry climate is the Giant White Squill (Urginea maritima), which is a member of the Asparagus family (Asparagaceae). This plant, which is from the Mediterranean basin, has an enormous bulb (perhaps the largest of any plant), and an unusual annual cycle. It grows in the winter: large leaves appear from November to about May, when they yellow and dry, and the plant goes dormant. Then, in late July, it sends up a dramatic flower spike, up to five feet high. Each spike has a raceme of hundreds of tiny white or pinkish-red flowers.

Click to enlarge. Giant White SquillClick to Enlarge Giant White Squill - CU Unusual plants that will grow w ell in your climate, can add a good measure of interest to your garden. Watch for exotic selections in your garden center or garden catalogs.

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The Giant White Squill has interesting characteristics.

  • All parts of the plant are toxic.
  • The flower stalks will continue to blossom after being cut, so you could bring a stalk indoors to watch the progressive opening of the blossoms.

For information about “uncommon and astonishing” plants, visit the website of Louis the Plant Geek. His website has information on many exotic plants, and includes photos of the Giant White Squill in leaf.

Gardeners oriented to reading could look for the book, Bizarre Botanicals, by Larry Mellichamp and Paula Gross (Timber Press, 2010). It could be in your local public library or book store, and is currently available on Amazon.com.

Wherever you find exotic plants for your garden, always favor plants that are suitable for your garden’s growing conditions. For most gardeners in the Monterey Bay area, remember that such plants are native to the Mediterranean climate region.

Be horticulturally adventuresome while increasing your chances for success!

Planning Garden Stairways

My garden includes a slight slope with a few stairs, made with 8” x 8” x 48” wooden highway ties. Earlier, garden stairs might have been made with railroad ties, which were often soaked in creosote as a preservative. Today, highway ties are pressure-treated with chemical preservatives, many of which are too toxic to be used near edible plants.

Happily, my short flight of aging stairs was not treated with a preservative, but consequently it is deteriorating and needs replacement. Wood is suitable for stairs that do contact soil, but in this case I will avoid rot by using flagstones or other natural stone. There are manufactured stone-like materials that also are available for such a project.

When planning garden stairs, first determine your preferred dimensions for the risers and treads. A six-inch riser with a fifteen-inch tread is a recommended combination, but other combinations also can work well. A steep flight of stairs might have seven-inch risers and eleven-inch treads, while a gentle flight might have four-inch risers and twenty eight-inch treads. See on gardening.com for the range of other good combinations.

Then, use a straight board and a carpenter’s level to measure the change in level from the bottom to the top of the slope. For a longer slope, use a garden hose, taking advantage of the fact that water seeks it own level. Hold the hose in a U-shape, with one end near the top of the slope and the other end near the bottom. Fill the hose with water, and adjust it so water is at the opening of each end. When this condition has been met, the two ends will be at the same elevation, and the distance of the lower end to the ground, minus the distance of the upper end to the ground equals the change in level. See ongardening.com for an illustration of this method.

Divide the change in level by your preferred height for the riser to determine the number of steps needed for that particular slope.

Then, measure the horizontal distance from the bottom of the slope to the top. Your preferred dimension for the tread times the number of stairs should equal that distance. If it does not, modify the riser and tread dimensions (using one of the good combinations) or include a curve in the flight of stairs or reshape the slope.

The width of the stairs is the next design issue to be addressed. The narrowest width could be two feet, which might be sufficient for a utility stairway. A one-person stairway should be four feet wide, which is generally considered the minimum for a garden path. A two-person stairway should be five feet wide.

Wider stairways, in scale with the landscape, can provide a visually striking appearance. This stairway at Les Quatre Vents, an estate near Quebec, is designed for grand entrances. (Click to enlarge)

Grand Staircase

Staircase at Les Quatre Vents, near Quebec, Canada

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Gardening in July

During this hot and dry month, the avid gardener should pursue seasonal tasks to keep the garden looking good and prepare for the change of seasons.

Irrigation should be a high priority to sustain plants that must have a ration of water during the drought. Pass by Mediterranean climate plants, which are accustomed to dry summers. A little moisture will perk up even these rugged individuals and extend their best days, but a better use of scarce water resources would target the garden’s thirstier specimens.

Roses, for example, could produce another bloom cycle during July if treated to a balanced fertilizer and watered deeply. Other candidates for regular watering are plants in containers, which can dry out fast.  First confirm that your water usage is within current restrictions.

If your garden consists mostly of Mediterranean climate and succulent plants, this year’s drought should not cause alarm. On the other hand, if you have a thirsty lawn, consider replacing it with plants of the summer-dry persuasion. The same strategy would be appropriate for plants from tropical, riparian or boggy areas.

Blossoms to enjoy in July include gladiolus, agapanthus and fuchsia, and fragrant Oriental hybrid lilies, e.g., pure white ‘Casablanca’.

Casablanca Lily

I am also enjoying blossoms of Chitalpa tashkentensis ‘Pink Dawn’ trees, which are crosses of catalpa and desert willow. They put on a show reliably around Independence Day, but opened a little earlier this year.

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The Corsican hellebores (H. argutifolius) have finished their winter-to-spring display, and leaned down their bloom stalks to drop seeds all around. The seasonal task is to cut stalks to their bases to make room for the new growth, which has already started.

The tall bearded irises also have finished blooming for this year. They will look best after the flower stalks are cut down, the leaves fade, and the rhizomes enter dormancy. Every four years, during the period from mid-July to mid-September, dig and divide the rhizomes to promote blooming for net spring.

In July and August, plant autumn-blooming blubs, e.g., autumn crocus (C. speciosus and C. sativus), meadow saffron (Colchicum autumnale), and spider lilies: Lycoris squamigera with lilac or rose pink blooms and L. radiata with orange-red blooms.

Control cool-season annual weeds, currently going to seed: bindweed, chickweed, crab grass, knotweed, lambs-quarters, mallow, pigweed, purple deadnettle, groundsel, nettle, purslane, speedwell and spurge, as well as field grasses. Dispose of seeds in the green waste not in the compost bin! The invasive cheery yellow Bermuda buttercup (Oxalis pes-caprae) has already faded, leaving clusters of bulbs to sprout next spring.