Agaves: living sculptures

Use these versatile plants for drama in pots and sunny gardens
Sharon Cohoon

 Agaves are living contradictions. Their perfect shapes - they're often likened to giant stylized roses or artichokes - make these strapping plants seem like the essence of order. But their wicked spines and leathery leaves remind you that the New World natives are plenty wild. That unusual combination of fierceness and symmetry makes agaves very useful in the West's most arid gardens. "These living sculptures provide incredible design opportunities," says Janet Rademacher of Mountain States Wholesale Nursery in Glendale, Arizona.

Landscape uses
In the desert, the muscular texture of agaves is a welcome contrast to the fine leaves of acacia, dalea, and most other trees, shrubs, and perennials. In Southern California, agaves can add drama to lavender, rosemary, and other narrow-leafed Mediterranean plants.

Agaves also give structure to beds of wispy wildflowers. Penstemon and desert marigold look twice as flowery and feminine with a few of these macho characters in their midst. The same goes for clarkia and poppies in California.

The sculptural shapes of agaves also make them perfect candidates for bold, contemporary gardens. They can be used alone with decomposed granite or gravel mulch and a few handsome boulders to create a desert version of a Japanese Zen garden. Or soften their strength by pairing them with ornamental grasses such as festuca, Mexican feather grass, and muhlenbergia or gentler-looking succulents such as aloes. See other planting combos here.

According to Mary Irish, former horticulturist at the Desert Botanical Garden in Phoenix, agaves also make excellent container plants because of their relatively sparse root system and their tolerance for crowding. Because they produce litter sparingly, they are especially good around pools, she adds. Moreover, a few species of agave, such as Agave attenuata, don't have spines.

Caring for agaves
The plants really do thrive on neglect. They tolerate most soils as long as they have good drainage, need only modest amounts of water, and rarely require fertilizer. Here are some guidelines:

Soil. Agaves are adapted to rocky, native soils and won't need amendments. But they'll tolerate rich, loamy soil if it provides good drainage. If your soil is heavy clay, mix some pumice or gravel into the backfill and plant your agaves on a mound.

Water. The first month or two after planting, irrigate plants every four or five days. After that, they should be established and will need little supplemental water. Irrigate twice a month in summer in the low desert and once a month elsewhere. In the winter, depending on rainfall, you may not need to water at all.

Fertilizer. With rare exceptions, agaves don't need feeding. In fact, fertilizing them may encourage flowering, which you don't want, since most agaves die after bloom.

Container culture. As in the garden, agaves in pots need good drainage. Try a mix of equal parts compost, potting mix, or garden soil, and either sharp sand, pumice, or gravel. (Don't use potting soil that contains peat moss). To prevent disease, position plans so the crown sits well above the soil line and will remain there after the soil subsides, says Arizona agave expert Mary Irish. Give plants a very light layer of slow-release fertilizer at the beginning of the growing season. Let containers dry out by at least half between waterings.

Pests. Agaves' only significant pest is the agave snout weevil. This insect tunnels into the center of the plant and lays its eggs. Infested plants show leaf wilt, followed by total collapse. The larger species, such as Agave americana, are the most susceptible. Unfortunately, there are few effective control measures. If the problem occurs, remove and destroy the infected agave along with any weevils or grubs you find.

If the enormous century plant ( A. americana), which can spread to 12 feet in diameter and grow leaves 6 feet long, has scared you away from agaves, come back for another look. Most plants in this family stay in the 2- to 4-foot-tall range - perfectly at home in small gardens - and some species are even smaller. Agaves come in a huge color range of greens, blues, and grays. One is just right for your garden.

More...