A recent column provided an overview of the genus Echeveria, called “Mexico’s Gift to Gardeners.” Today, we take a look at the genus Agave, another of Mexico’s gifts to gardeners, with value for larger settings.
Agave species grow naturally through the southwestern United States, Mexico and Central America, Columbia and Venezuela in South America, and the Caribbean islands.
All Agaves are monocarpic, i.e., they die after flowering. Unlike many annual plants, Agaves can grow for several seasons before flowering, setting seed and dying. For this reason have been called “multiannual.” They have also been called Century Plants, but they flower and set seed in much shorter periods, generally when conditions are right to support propagation.
There are two basic vegetative types of Agaves. One type produces offsets (called pups or babies) either in the leaf axils or through underground stems. The other type, called the solitary Agaves, propagates only by producing seeds.
These types are important for placement in the landscape. An offsetting type Agave needs ample space to allow for full development of a larger cluster of plants, while a solitary type Agave needs only enough space to accommodate its mature size.
Agaves generally consist of leaves arranged in a spiral, forming a rosette. The leaves might be thick or thin, succulent or fibrous. Some Agaves have smooth leaf edges, while others have sharp teeth along both sides of the leaf. Some species have leaves with terminal spines, which might be stout and quite sharp.
The rosettes come in several size categories, depending on the species. The smallest can be three inches tall and four inches across, and the largest can be ten feet tall and twelve feet across. Likewise, the flower stalks vary in several characteristics, including height that in some species, e.g., A. americana, can reach up to thirty feet.
There are over 200 species of Agaves. Of these, about 80 are found in gardens, and only about ten species are commonly grown. The typical home gardener in the Monterey Bay area will be familiar with three or four species.
Agave americana, which grows to large dramatic form, is widely cultivated worldwide for its ornamental value. The rosette of A. americana can spread to six-to-ten feet in diameter, and its flower stalk, as noted above, can reach thirty feet. At east six cultivars are available, with different patterns of white or yellow striping on the green leaves.
Agave attenuata gets its specific name from the leaves that shrink to a point. This plant has an unusually curved stem, which is revealed as leaves age and fall off. It develops a rosette of six-to-eight feet in diameter, and produces a flower stalk up to ten feet long. The stalk typically will reflex towards the ground, then arch upward again. This growth pattern gives the plant the common names, the Fox Tail Agave or Lion’s Tail Agave or Swan’s Neck Agave. Because this plant lacks teeth along the leaf margins, or terminal spines, it presents no hazards in the garden.
Agave tequilana, the Blue Agave, produces large amounts of sugars, mostly fructose, in the core of the plant, making it particularly suitable for preparing Mexico’s well-known tequila and other alcoholic beverages. This plant can grow to over seven feet tall, and produce a stalk up to sixteen feet high. A. tequilana has as much landscape value as other Agave species, but is most widely grown commercially.
Agave victoriae-reginae, known as Queen Victoria Agave, is a smaller plant, growing slowly to 12 inches tall and 18 inches wide. It is popular as an ornamental for its streaks of white on sculptured geometrical deep green leaves. The leaves lack marginal teeth, and sometimes have short terminal spines. The flower stalk, which can reach up to fifteen feet, displays reddish-purple flowers. This is the only solitary type agave of the species listed here.
Agaves are drought-tolerant, easily grown plants that can bring dramatic architectural forms to the landscape.