Family: Agavaceae
Common Name: Century Plant

Native to South and Central America, this genus includes around 300 species, many of which have been cultivated commercially for the fibers in their leaves and 'pulque', the main ingredient for local alcoholic beverages in Mexico. Widely distributed in their native habitat, some species have also become naturalized in various parts of the world. They come in various sizes, from giant rosettes of 2-3 m (6-10 ft) in diameter to tiny ones as small as 2 cm (1 in). The common name was adopted because it was originally believed that the plants flowered only every 100 years. It is now known that some flower after five years, while others flower only when they reach 30-50 years of age. All species have succulent leaves and flowering stems which emerge from the center of the plant as a mast-like stalk, which grows extremely fast and tall. From this, some species produce branched inflorescences with numerous flowers which are self fertile. Some species also produce little bulbs in the axils of the flowering stem, which facilitate propagation.

Species

A. americana, which is grown outdoors in the south-west US region, grows to 3 m (10 ft) tall and quite wide. A stemless rosette, it has thick, fleshy, strap-shaped leaves, blueish in colour, with marginal teeth and a sharp point. Offsets are produced freely. The flowering stem, which appears after about 30 years, is 5-8 m (16- 26 ft) tall. All of the cultivars have shorter leaves than the species itself and various markings. 'Marginata' has yellow margins on its leaves; 'Medio-picta' has a central yellow stripe; 'Striata' has thin, rather random, longitudinal yellow stripes.

A. attenuata branches from the base to form a large clump. It is a softer, dense rosette of pale green leaves with neither spines nor teeth. The tall stem grows to about 3 m (10 ft), curving over to form a floral arch. The flowers continue to bloom for several months.

A. parviflora grows to only about 15 cm (6 in) in diameter. It has hard, stiff, narrow leaves, marked with white lines, a terminal spine and white threads hanging from the margins of the leaves.

A. sisalana, sisal hemp, a very large species from Mexico, is cultivated for fiber in various parts of the world.

A. victoriae-reginae, a very striking species from Central America, grows symmetrically to about 60 cm (24 in) in diameter. A dense rosette, it has dark green, narrow, keeled leaves, marked and edged with white. After 20 years creamy yellow flowers appear in spring and summer.

Cultivation

In frost-prone areas these plants are grown in a cool glasshouse or conservatory. They can be stood outside for the summer or used in summer bedding displays. They like very well-drained, gritty soil or compost. Under glass provide really bright light but shade from very strong sun as it may burn the foliage. Outdoors provide a position in full sun.

Climate

Grow in frost-free areas; zone 9 and above.