Mini-Show Succulent September 2015: Agave, Calibanus, Nolina, Yucca
The genus Agave is part of the family Agavaceae. There are around 200 species in the genus. Most of these are from Mexico, although they occur in the southern United States and into South America.
Plants are characterized by forming rosettes of fleshy (succulent) leaves which have a sharp point or spine terminally. The leaf margins may be smooth or spiny.
Agave plants have been given the common name “Century Plant” because of their blooming habit. The idea is that the plants live for 100 years, bloom and die. While it is true that Agave are monocarpic, meaning they bloom once and then die, few species, if any, take a full 100 years to do this. When an Agave does bloom, it sends up a large flower stalk out of the center of the plant that grows very quickly. The height of the bloom stalk is often many times higher than the plant. This often catches people by surprise when the Agave they were growing in their garden for years, suddenly and rapidly goes through this transformation. This is often when they try to identify and learn more about their plant.
Because of the fleshy green succulent leaves and the sharp points, many people try to look up cactus or cacti when in fact it is an Agave they are searching for.
Calibanus, nolina, and yucca are all members of the Agavaceae family. The Agave family, like the Cactaceae family, is entirely new world in origin, although many members have been naturalized around the world.
Although many of the members of this family grow very large with age, they are particularly good looking as seedlings, and can be kept small for many years in pots. All described below are easily grown in Southern California. They can remain unprotected in pots or the ground year-round. They thrive with regular feeding with any general purpose fertilizer. Their appearance is best when they are cleaned regularly, with debris removed from the leaves, and dead leaves removed to prevent insects from making homes.
Calibanus is a monotypic genus, consisting of Calibanus hookeri from central Mexico. Calibanus hookeri has a hemispherical caudex covered with a gray to dark brown thick bark. The leaves are grass-like, and are produced in tufts. Readily available, and hardy in Southern California, this plant will grow quickly if placed in the ground for a few years. It’s worthwhile growing a few because the caudices vary in shape, pattern and texture.
Some of the best caudexes are produced by abusing the growing plant, and turning the pot on its side for all or part of a growing season. This produces the most interesting shapes, and the best looking plants. Many growers will cut off the trunk periodically to force new branched growth and more growing tips. All of these help produce the caudexes with great character that frequently grace our shows.
Nolina, native to California Arizona, New Mexico, Texas and Mexico is a genus of long leafed shrubs to small trees that do well in local gardens.
Many members of the Nolinaceae are characterised by stout succulent caudexes or swollen trunks storing water and food reserves, while supporting relatively thin, wiry leaves.
Members of the Nolinaceae are found in the Southern states of the USA and through Mexico into Guatemala. Unlike most Agaves, all members of the family Nolinaceae are polycarpic and dioecious, with decorative spikes of numerous small creamy-white flowers, sometimes tinged with pink or purple.
Yuccas occur exclusively in the Americas, distributed over a wide area from Canada into Central America and the Caribbean with species adapted to dry deserts, grasslands and tropical rainforests.
There are at least 50 species of Yucca notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitish flowers.
Yuccas are widely grown as architectural plants providing a dramatic accent to landscape design. They tolerate a range of conditions, but are best grown in full sun in subtropical or mild temperate areas. Joshua trees (Yucca brevifolia) are protected by law in some states. A permit is needed for wild collection. As a landscape plant, they can be killed by excessive water during their summer dormant phase, so are avoided by landscape contractors.