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)

 

Some Garden Thugs You Want Around

A weed is simply a plant growing in the wrong place, while a garden thug is a plant spreading without apparent limit, and overwhelming other plants it encounters. Garden thugs could well be landscape assets, given freedom to expand. Here are three examples from my South African succulent bed.

Thug #1: Aloe maculata (Soap Aloe)

Aloe-maculata-Soap-Aloe

Some 550 recognized species are included in the genus Aloe. One of them, the Soap Aloe (its sap makes a soapy lather in water) is among the most popular Aloe species in California gardens. The plant forms a rosette about a foot wide, made of pointed fleshy leaves about eight inches long. In the spring it sends up a two-foot long stalk topped by orange-red flowers in a flat-topped cluster called a raceme. So far, so good, but it also sends underground suckers that soon create a dense colony. I lifted ten plants for this month’s garden exchange, then put another eight in the green waste.

Related species in my garden include A. arborescens (Torch Aloe), also a vigorous grower; A. plicatilis (Fan Aloe), a slow-growing small tree; and A. ‘Christmas Carol’  (hybrid), a smaller plant with vibrant red colors in the leaves. In this group, Soap Aloe is the real thug.

Thug #2: Senecio mandraliscae (Blue Finger)

Senecio mandraliscae

Senecio is one of the largest genera of flowering plants, with about 1,250 species that present many amazing forms. Blue Finger, which might be a hybrid, grows twelve-to-eighteen inches tall, with numerous four-inch long blue-gray leaves shaped like fat bean pods. It produces uninteresting white flowers in summer but the foliage is the main attraction. The leaves will drop easily from the plant, and root to form new plants. The spreading stems also quickly establish roots.

A nice-looking succulent plant and a welcome addition to the garden, but one that needs regular whacking to keep it within bounds. My other Senecios are S. rowleyanus (String-of-Pearls) (showing the variability of this genus) and S. haworthii (Wooly Senecio). There could be other thugs in this large genus, but Blue Finger certainly qualifies.

Thug #3: Cotyledon orbiculata (Pig’s Ear, Paddle Plant)

Cotyledon-LSCotyledon-CU

This striking succulent has gray-green fleshy leaves with red margins, and coral red, bell-shaped flowers on stalks in early spring. The leaves grow on stout branches growing any way other than straight. This attractive plant spreads over time, and is considered invasive in some parts of the world. The plant has medicinal uses, but its leaves are said to be toxic to livestock, poultry and dogs. It works well in containers, which might well be the best place for this plant.

These vigorous plants will prove you have a green thumb, but they require control.

Mulch for Much Easier Gardening

Mulching represents a gardener’s not-so-secret strategy for achieving the universal objective: a low-maintenance garden.

If your garden is time-consuming, frustrating and disappointing, it probably needs mulching.

Several other possible causes should be considered: nutrient-poor soil, lack of irrigation, inappropriate plant selection, etc., but let’s focus for the moment on mulching.

A three-inch deep layer of an organic mulch between plants discourages weed growth, conserves water and, in time, breaks down to add nutrients and texture to garden soil.

We should not ignore the downsides of mulching. For example, a larger garden will require several cubic yards of organic mulch, leading to significant charges from a landscape supply company for the material and its delivery. In addition, distributing the mulch within the garden, while not difficult, consumes time and energy.

One more downside: organic mulches decompose in time, so the time and expense will have to be incurred again. Finer mulch materials break down faster than coarse materials.

Some organic mulch is free, e.g., disease-free wood chips that tree services will dump on your property, upon request (to avoid landfill charges), or seaweed harvested during low tide. Wood chips might be regarded as less attractive than finer mulches, and seaweed, although excellent in nutrient content, often is troublesome to gather, buddy and smelly.

A landscape supply company will offer a variety of organic mulches in bulk, e.g., redwood sawdust, shredded cedar, fir bark and gorilla hair (shredded redwood bark, really), in a range of sizes and prices.

Another option is cocoa shell mulch, which is available in bags of two cubic feet for about $5.00. This material looks good, emits a nice fragrance and breaks down slowly, but contains theobromine, a natural compound that if eaten is highly toxic to dogs and cats.

The gardener could consider each of the available options, and perhaps try a sample bag in the garden.

Home supply stores offer organic mulches in bags of two cubic feet of material. These can be appropriate for smaller beds, but for larger projects will be more expensive than bulk materials. To move one or two yards of mulch, it’s good to have a friend with a pickup truck.

Gravel mulch might be preferred for a rock garden or succulent garden. For a rock garden in particular, gravel mulch simulates scree, the debris of broken rock seen on mountain slopes.

Like organic mulches, gravel mulch discourages weeds, conserves moisture and looks better than bare soil.  Gravel is much more expensive per cubic yard than organic mulches, but a one-inch layer should be enough and gravel doesn’t decompose. Gravel mulch is difficult to remove, so for practical purposes treat the installation as permanent.

Enjoy your mulched garden.

More

Estimating Mulch Needs

To decide how much material you will need, estimate the surface area of the garden bed(s) to be mulched: length times width (in feet). Multiple by the intended depth of the mulch layer: for a three-inch layer, multiply by .25. Finally, convert cubic feet to cubic yards by dividing by 27.

Example: a 12 feet x 18 feet garden bed has a surface area of 216 square feet. For a three-inch layer of mulch, .25 x 216 yields 54 cubic feet. Divide by 27 to determine a need for two yards of mulch.

Seaweed Mulch

An interesting article, How to Use Seaweed to Mulch Your Garden, is available on the website for Eartheasy: Solutions for Sustainable Living. Gardeners who live close to the beach might wish to try this mulch material, but it seems too smelly and buggy for my taste. It also decomposes into slime rather quickly.