In the Garden
pot luck

Pots, cans, hollow logs, and other makeshift containers introduce a unique new look to your garden.

By Judith Phillips
Photography by Charles Mann

This article first appeared in Spring 2009 Su Casa

Landscaping in the arid Southwest has its difficulties. Rather than take a pickax to the cemented surface that sometimes masquerades as soil here, it’s tempting to resort to cultivating in pots as a respite from the extreme sport of gardening. Container growing allows you to provide more user-friendly potting soil and tame the blazing sun by placing pots under overhangs and in niches where they can escape the full throttle of heat, cold, and wind. Conveniently, the best places for container gardens in the desert tend to be where people spend the most time outdoors: sheltered patios, porches, and courtyards, where plants in pots take the stage like stars. They may be intended to grace a space for several years with only minor refreshing, or to be seasonal, designed for a limited show time and replanted as changing seasons or inspiration dictates.

select your plants
When pursuing a perennial performance that’s long and productive, your plant selection requires careful scrutiny. Soil insulates so effectively that the roots of many plants are 10 to 20 degrees less cold hardy than the top-growth—buried in the soil, they are normally more protected from the extremes. Even in the largest pots, plants’ roots are often exposed to greater cold in winter and heat in summer than they would be in the ground. It’s generally a good idea to opt for plants that are at least as cold hardy as the place you live. If the pots will be in open and exposed areas, the plants should be at least one USDA zone more cold hardy than they’d need to be if planted in the ground, and they should be tolerant of summer heat as well. Windy full-sun exposures are especially hard on potted evergreens and plants adapted to cooler or more humid climates, as their leaves may lose moisture faster than they can absorb it from the limited soil reservoir in containers.

In addition to considering ambient temperatures, match the plants to the water and light available. The potting soil should hold moisture but drain well: a mix of half compost, one-quarter sand and one-quarter scoria fines or pumice fines (gritty crushed volcanic rock) will work well for most plants. Less compost and more sand and scoria work for cacti and most succulents. Amendments like DriWater or polymer gels that release moisture slowly as well as time-release fertilizers can reduce day-to-day maintenance.

choose your container
While the plants provide the starring attraction, containers contribute both color and form. You could choose tall slender pots glazed pale celadon or deep red; urns, cubes, tubs, bowls, or troughs in terra cotta, slate, or copper; or faux-glazed Euro foam pots. The options may seem endless, but practical considerations will help to narrow the field. Pots outdoors year-round need to weather repeated freezing and thawing or you’ll need to replace them every few years. If you’ve already selected the plants, finding a pot that will best accommodate and offset them is your holy grail.

To make shopping easier, take photographs of the plants with you as you seek out the perfect vessels. If you’ve already selected the containers for their brilliant colors, clean architectural lines, Zenlike serenity, or funky attitude, determine which plants have the understatement or opulence, élan or whimsy, and the stamina to live a self-contained lifestyle.

Think big and mix it up. Large containers have the greatest dramatic potential as well as the most room for plant roots to grow—a minimum of 18 inches by 22 inches or as large as budget and space allow. Big pots have space for a combination of two or three plants to complement each other. Smaller pots with a single plant in each can be clustered for greater effect. Play with the proportions.

design your container garden
Generally low flattened bowls or troughs call for a mix of plants not much taller than the container, such as a mosaic of succulents or fine-textured herbs. In squatty containers, hens and chicks, cheddar pinks, and blue spruce sedum offer a nice blend of evergreen shapes, colors, textures, and ephemeral fragrance when the pinks bloom in spring. Dwarf yucca mixed with English thyme and desert zinnia is a sun-loving trio for wide-topped bowls.

Pots of near-equal height and diameter might call for a mix of plants: an anchor specimen nearly twice the height of the pot, another plant of intermediate height and contrasting color or texture, and a third variety to cascade over the container’s edge. A space with sun in the early part of the day or a spot with afternoon sun filtered through a canopy of leaves from a nearby tree or an arbor prove ideal locations for a display of pots. You can achieve simple but striking combinations with tall ‘Matrona’ sedum, blue oat grass, blue avena, or evergreen soft-leaf yucca surrounded by ‘Herrenhausen’ or ‘Hopley Purple’ oregano and Greek germander or yellow iceplant.

In full sun, an artichoke-like rosette of New Mexico agave surrounded by flame flower drifting on wiry gold stems in a bowl wider than it is tall makes a powerful vignette. The aromatic curlicue foliage of ‘Seafoam’ artemisia paired with the dusky plum seed heads of ‘Moudry’ hardy pennisetum with a dash of ‘Purple Shamrock’ oxalis will make sure everyone’s paying attention. You can create a subtle effect with the narrow lacquered leaves of beargrass emerging from a mass of yellow pineleaf penstemon or the lithe vertical grass ‘The Blues’ little bluestem mixed with Wright’s buckwheat, a silver-stemmed wildflower with white flowers in summer that gradually dry to rust-colored seed heads in autumn as the grass fades from blue to pink to rust. In deeper shade, the very vertical ‘Karl Foerster’ feather reed grass mixed with bigroot geranium and yellow iceplant will transition the seasons with grace. Pots much taller than they are wide might have a centerpiece half the height of the pot, perhaps another strongly vertical grass such as ‘Jose Select’ tall wheatgrass or a bundle of dry salt cedar twigs.

For those of us who like to play in the dirt and perhaps even dine on the fruits of our labor, pots may be composed of tender annuals in spring and replanted in late summer with cold-tolerant ones. Purple fountain grass pairs well with dwarf eggplant or purple basil for summer, replaced with mixed Swiss chard and leaf lettuce in early autumn. Purple basil teams nicely with pink-flowered chives, both in a pot and on a plate. In springtime when the urge to plant is strong and nurseries are full of possibilities, maybe I’ll see you browsing the aisles. I’ll be the one wearing a straw hat with a huge pot in my cart and a grin on my face.

A widely acknowledged expert and author on regionally appropriate gardening, Judith Phillips has designed more than 1,000 residential gardens, collaborates on design teams for public landscape projects, teaches a native and xeric plant class at the University of New Mexico, and has written four books about landscaping in the Southwest.

Natural selections
Bigroot geranium (Geranium macrorrhizum)
Blue oat grass or blue avena (Helictotrichon sempervirens)
Dwarf yuccas (Yucca neomexicana or harrimaniae)
Desert zinnia (Zinnia grandiflora)
Flame flower (Phemerantha syn. Talinum calycinum)
New Mexico agave (Agave neomexicana)
Soft-leaf yucca (Yucca recurvifolia)