Dramatic agaves are water-savers

Ever since I saw a photo of the magnificent Agave attenuata with pale green succulent leaves, I’ve been captivated by it. This agave (ah-GAH-vay) was a youngster, potted up and sitting on a dining room shelf where it must have been enjoyed for only a limited time; for, with age, it becomes very large, reaching out nearly 2 feet from the main stem, too large for a houseplant and, for some, too large for the garden. I’ve yet to add it to my own my garden but one of these days, I will.

This century plant, as agaves are commonly called, has many appealing qualities. Its spineless, sword-shaped, thickened leaves unfold in an open, slightly flattened rosette while maintaining a rigid conical center — all striking architectural elements. While not translucent, the leaves often appear that way and sometimes show a very narrow cream or red margin.

Several other agave species are just as fascinating — if you appreciate water-saving succulents or geometric forms or even painterly hues mingling within the leaf of a single plant — and many are restricted in size, making them popular potted plants both indoors and out as well as dramatic additions to drought-tolerant gardens.

Century plant is an unfortunate misnomer, suggesting that plants bloom only once every 100 years, which is not at all the case although the interval between bloom periods is long.

In reality, agaves as a group bloom rather inconsistently and infrequently, often only at 10 to 25 years of age. When they do bloom, clusters of tubular flowers appear on what looks something like a giant asparagus stalk. You’ve undoubtedly seen them on the huge blue century plant (Agave americana) that has been planted in many North Bay landscapes.

Small offsets sprout around the base and form clumps that can become mountainous in large species and difficult to remove. But offsets are prized because they can be separated and replanted as new specimens, an especially important feature since the parent plant of most agaves dies after flowering.

Smaller agaves are relatively easy to handle and rarely grow out of control. Some of these are diminutive versions of larger species. Agave Cornelius (aka Quasimodo), for example, is a 12- to 18-inch version its larger form, the giant green and yellow striped century plant (A. americana Marginata). The undulating leaf margins and small colonies of offsets make A. Cornelius a terrific garden plant.

On many agaves, individual leaves bear dark, hooked spines up and down the margins of thick, succulent mostly upright leaves. But not all are so wicked.

A. celsii Multicolor from the northern Mexico cloud forest has creamy margins on broad, pale green succulent leaves that bear very small, less threatening spines. This form adapts to sun and shade and stays under 12 inches high and wide.

A. parryi, on the other hand, is one of the most beautiful and popular species and has some of the most vicious, dark and spiny leaf tips. It forms a compact rosette with each pale blue leaf bearing a lasting imprint of those that unfurled from the center before and after it.

One of the most regal looking agave species is the aptly named A. victoriae-reginae. Dark green, thickened and succulent, triangular leaves show white markings and form a fairly tight, blunt rosette with short spines on leaf tips. It grows about a foot high but nearly twice as wide. There is a dwarf form that takes the shape of a compact, very symmetrical ball.

A few agaves develop very narrow, rounded leaves like knitting needles that radiate out from the center to form domes or half domes. Agave stricta appears as a yellowish green 2-foot sphere on a shortened stem. Agave striata is shorter initially but continues to pile up prickly grayish green balls after flowering. Both have needle-like points on leaf tips.

Retail nurseries generally carry a few agaves, but for a wider selection, pay a visit to Lone Pine Gardens, 6450 Lone Pine Road, off Highway 116 south of Sebastopol (823-5024) where succulents are one of their specialties. Hours are 10 a.m. to 5 p.m. Thursday, Friday and Saturday except in late December and early January.

Many mail-order nurseries carry even larger numbers of agaves. Plant Delights in North Carolina (www.plantdelights.com) has an impressive though somewhat expensive collection — including nearly all of the above mentioned choices — which they consider to be affordable.

If you do purchase expensive plants, take care to give them a spot sheltered from wind in fast-draining soil, amended if necessary with lava rock or pumice and built into a slight mound that rises above saturated soil in winter.

In summer, provide ample water to keep agaves from shriveling and be sure to fertilize in poor soils. Although these are succulent species that store water, they must have sufficient supplies during the growing season so they can hoard it for later use if needed.

Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the weekly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 664-9476.