In the Garden

succulent solutions

From agaves to yuccas, these juicy plants perk up the dreary winter garden with living sculpture and a cheerful green promise of spring to come.

By Judith Phillips
Photography by Charles Mann

This article first appeared in Winter 2008 Su Casa

The pulse of passing seasons is one of the things that keeps me gardening. Spring’s phoenix-rising energy, the wild exuberance of early summer and blowsy redolence of late summer turning to autumn all have abundant charm, but since I’ve been gardening in the desert, it’s the soothing simplicity of winter I have grown to love best. Every garden can become more contemplative, more Zen-like as the winter solstice approaches. When hard freezes have blackened the last blossoms of the growing season, most of the leaves have turned from shades of green to gold, copper, or rust and sifted slowly to earth. Any persistent foliage takes on somber tones of loden, plum, and steel gray, bronze, and platinum. The garden is pared down to its bare bones. Branch patterns, the mass and contours of tree trunks, and the texture of bark, wall surfaces, and paving patterns assume greater significance as the impressionist landscape fades and its minimalist composition emerges.

Most conifers and broad-leafed evergreens, the mainstays of Temperate Zone dormant interest, are out of their element in the desert. In the dry air, alternating daytime warmth and nighttime cold scorch leaf margins, creating an aura of winter discontent. Ornamental grasses add a spark to the somnolent garden, but one heavy, wet snowfall can drape a party’s-over pall over their display as well. In desert gardens the ideal plants for winter interest are those that have thick-skinned leaves that resist the drying effect of frigid winds, plants substantial enough to be snow laden one day and sunbaked the next, with striking shapes, foliage, or stems of intricate detail or bold line that capture the low-angled sunlight. The winter-winnowed stage is the perfect showcase for architectural desert plants—succulents and cacti grown as living sculpture in the landscape.

All cacti are succulents—plants that store moisture in their stems and/or leaves and sometimes in specialized root structures as well. But not all succulents are cacti—plants with body armor, spines that resist foraging wildlife and sometimes deter gardeners who’d rather have a softer, gentler landscape. Many widely used garden plants with thorns are not cacti—roses and pyracantha among the more familiar, mesquite and jujube among the more xeric—but cacti are synonymous with prickly personalities. Along with their brilliant floral displays and padlike, canelike, or clustering, mounded forms, their array of spines is a distinguishing feature that crowns an impressive garden presence, especially when cacti are planted in raised beds or large pots where light glancing off the spines glows a deceptively soft halo.

Our relatively cold high desert winters limit somewhat the selection of succulents and cacti that will thrive here. Succulents adapted to cold are able to concentrate the sugars in their sap as a kind of antifreeze; they reduce the moisture in their cells as days become shorter to provide room for expansion when the remaining moisture freezes and thaws within the cell walls. As a result, the large pads of Engelmann and cow-tongue prickly pear tend to recline, and the tips of cane cholla droop to accommodate the cold.

Some of my favorite succulents are those in the agave and lily families: agaves, hesperaloes, nolinas, and yuccas. These are all rosettes in form—their leaves swirl outward from a central growing point—but that common feature spawns an amazing variety of individual personalities. And the same structural strength that funnels rainfall to their roots during the summer makes them indifferent to harsh blasts of winter as long as the soil is dry.

Most cold-hardy agaves are stemless—their crowns hug the ground while their leaves may unfurl to cover a space two feet or wider. Some grow offsets that nestle around the base of the main plant like giant hens and chicks, others are solitary, and still others such as lechuguilla grow a thicket of offsets, making a ground cover that is a very effective traffic barrier. Parry agave and New Mexico agave resemble huge sculpted artichokes. They are large enough to repeat in several places, establishing a rhythm through the garden—you can hardly ignore agaves, yet they are elegantly composed, and they are exquisite up close, where you can see the impression of leaves upon one another as they spiral from the center. Agaves are long-lived, though they don’t attain the dotage that their common name, century plant, suggests. Producing the tower of flowers, typically 10 feet or taller with nectar-rich florets that are very attractive to hummingbirds and bats, takes so much energy that plants die as a result. Once the show is over, the garden space is open to a new idea or replacement with an offset of the original.

Hesperaloes are the only large succulent lily with colorful flowers. Red yucca is the most commonly used one with a grassy mound of leaves three feet tall and at least four feet wide, overshadowed through much of the growing season by arching stems of waxy coral blossoms that on mature specimens may grow six feet tall. There is also a form with butter-yellow flowers. Giant hesperaloe is a lesser-known species with broad bright-green leaves and creamy white flowers on stems 12 to 15 feet high.

Nolinas are a lily of another sort. Our local bear grass and big bear grass from the bootheel of New Mexico resemble huge clumps of khaki-green grass; their long slender lacquered leaves end in coarse curling fibers. Bear grass is nearly stemless and holds its frothy flower stalks close within its leaves, while big bear grass forms a short trunk and even while young develops a flower stem six feet or more in height. Blue nolina is another tree-form species slowly growing eight feet or taller with handsome blue-green leaves and contrasting chartreuse flower spikes.

Yuccas are the most ubiquitous and varied of our native succulents. Palm yuccas are the tree species collected from rocky slopes in southern Texas and northern Mexico that have been used as accent specimens in Albuquerque landscapes for at least 40 years. Considering the number of plants uprooted and hauled north, it’s surprising there are any left in the wild, and so the common name is wryly appropriate, as the native palms of the Sonoran and Mojave desert oases are now mostly found lining the boulevards and casino parking lots of Las Vegas. Our native soaptree is less likely to survive wild collecting because of its deep water-storing root, but smaller nursery-grown specimens are available for gardeners willing to wait a decade or so for plants to reach eight to ten feet in height. The rewards for such patience are flower stems equal or greater than the height of the plant, reliably produced each July just when the heat sends most blooming plants into siesta mode. At the opposite end of the scale is New Mexico yucca with narrow blue leaves in small clumps barely a foot high. Lechuguilla offsets new plantlets linked to the main plant by thick roots just beneath the soil’s surface, forming a low profile and extremely low-water ground cover if plants are spaced two to three feet apart. For continuous summer color, scatter flame-flowers, a succulent perennial wildflower with deep rose-colored blossoms on wirelike gold stems, between the wee yuccas.

Between the titanic and the tiny are dozens of yuccas with garden appeal. Joshua tree and Thompson’s yucca are two multiheaded species; Joshua trees can easily grow fifteen feet tall while Thompson’s yucca tops out at six feet, but both can have dozens of heads, many producing the typical candelabra flower stems each year. Other tall specimens include beaked yucca, with narrow pale-green leaves outlined in yellow, usually single-headed and slow-growing to 10 feet, and Mexican blue yucca, which is similar in size but has wider pale-blue leaves. Of the short-stemmed or stemless species, soapweed is heat-loving and drought-requiring, perfect for really difficult spots, and Spanish dagger, or datil, has wider, curved leaves that tolerate quite a bit of shade. Both plants develop multiple rosettes and eventually need a space four feet high and six feet wide.

Not every sentence should end in an exclamation point, but succulents are an excellent way to punctuate the winter landscape, and the larger the garden, the more opportunities there may be to add such focal points. A new book from Timber Press, Designing with Succulents by Debra Lee Baldwin, is full of pertinent design insights such as the observation that rosette-forming succulents orient themselves toward the sun so you can use exposure to direct the growth of plants away from paths, a critical concern when plants are large and lethally armed. There’s also much attention given to pairing plants, amplifying or softening their impact. While focal accents are the stars, a supporting cast of xeric plants provides the seasonal color and textural contrast that keeps the picture lively. Although many of the gorgeous images feature plants that aren’t cold hardy here, the photos do offer ideas for using plants with similar forms that are hardy, and the book has a section entirely devoted to cold tolerance.

A trip to the bookstore could be the beginning of a new era in your garden’s evolution. With Designing with Succulents in mind, now is the time to assess the landscape for places in need of accenting. Because succulents store so much moisture and need warm soil to root into, winter is the season to plan their introduction into the garden, deferring the actual planting until late spring or early summer. In gardens that are more heavily watered, succulents need to be on high ground and watered much less often than the rest. While most succulents need at least a half-day of sun, the broad-leafed agaves, blue nolina, and softleaf yucca grow well in more shade as long as they aren’t watered too much. If you have a garden in need of some excitement, there is likely a succulent that will add the spark and save water as a bonus.

A widely acknowledged expert and author on regionally appropriate gardening, Judith Phillips has designed more than 900 residential gardens, collaborates on design teams for public landscape projects, and teaches a native and xeric plant class at the University of New Mexico.