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Taxonomic name: Agave americana L. Synonyms: Agave rasconensis Trel. ex Standl., Agave zonata Trel., Aloe americana (L.) Crantz Common names: agave, agave d'Amérique (French), American agave, American aloe, American century plant, American-aloe, Amerikanische agave (German), century plant, garingboom (Afrikaans), Hundert-jährige agave (German), maguey, maguey americano (Spanish), pita común (Spanish), pite (French), spreading century-plant, wild century-plant, yucca Organism type: herb, shrub Agave americana is a large, rhizomatous succulent that grows in a wide range of conditions including cliffs, urban areas, woodlands, grasslands, riparian zones, beaches and sandy areas, and rocky slopes. A. americana is tolerant of wind, salt, high temperatures, and extreme drought. It can grow in shallow, very dry, low fertility soil and can colonise bare sand. It is grown for many reasons- ornamental, medicinal and agricultural. In South Australia Agave americana mainly invades disturbed sites, road sides and coastal vegetation. It may also harbour introduced animal species, such as rabbits, making feral animal control more difficult. Description Agave americana is a large and stemless succulent, with leaves that can grow up to 2 m. Leaves are robust and spear-like, and are in a basal rosette. The leaves have sharp hooks or spines on the edges, and very sharp tips. Leaves have stomata which open at night, taking in carbon dioxide. Flowers are yellow and occur rapidly after maturity, when the plant is 10 - 15 years old. Flowers are at the top of a long stalk (up to 10 m), and are branched, candelebra-like, from the main stalk. These are followed by seed capsules with seeds (black, 5 cm long). The plant dies after fruiting (Badana & Pugnaire 2004; Harris 2008). Similar Species Furcraea spp. More Occurs in: coastland, desert, natural forests, range/grasslands, riparian zones, ruderal/disturbed, scrub/shrublands Habitat description Agave americana can grow in a wide range conditions, including cliffs, urban areas, woodlands, grasslands, riparian zones, beaches and sandy areas, and rocky slopes. A. americana is tolerant of wind, salt, high temperatures, and extreme drought. It can grow in shallow, very dry, low fertility soil and can colonise bare sand (ARC 2007; Badano & Pugnaire 2004; Bezona et al. 2009; Le Houérou 2000). General impacts One of the major impacts of Agave americana is its large leaves shading out native plant species. A. americana also has a very dense network of rhizome offshoots, which could draw resources away from native species. The rhizomatous nature of A. americana could also alter the nutrient status of the soil. A. americana may have adverse effects on human and animal health (Badano & Pugnaire 2004; Macdonald et al. 2003; NPPA 2008; Williams 2008). Uses Agave americana has several uses: ornamental, medicinal, as a vertebrate poison, agricultural, fodder, erosion control (USDA-ARS, 2010). A. americana is grown as an ornamental on all continents, except Antarctica (Nobel 1990). Fibres derived from A. americana have been shown to be more extensible than other natural fibres, and also exhibit high tensile strength and are low density and have a high moisture content (Msahli 2000, in El Oudiani et al. 2009). Ropes and twines made from A. americana fibre were important agriculturally (otherwise) in North Africa up until the 1960's (El Oudiani et al. 2009; Jaouadi et al. 2009). A. americana is grown in South Africa as a fodder crop, although it cannot be directly grazed and requires processing before feeding (De Cock 1980; Le Houérou 2000; Myburgh 1994). A. americana is also used to brew an alcoholic liquor beverage, in Mexico and South Africa (Boguslavsky et al. 2007). A. americana is used in Mexico, Brazil, India and China as a traditional treatment, as it has anti-inflammatory, anti-bacterial and anti-fungal properties and can be used as a diuretic (Boscolo et al. 2010, Jin et al. 2004; Parmar et al. 1992; Peana et al. 1997; Rivera et al. 2010). Notes A. americana sap can cause pain and dermatitis in humans if it comes in contact with skin (Kerner et al. 1973; Ricks et al. 1999). The sap has also been shown to have anti-bacterial, anti-fungal and anti-inflammatory properties (Jin et al. 2004; Parmar et al. 1992; Peana et al. 1997). A. americana appears in the FDA Poisonous Plant Database (McGuffin et al. 2000). Direct children of A. americana: A. americana ssp. americana L.; A. americana ssp. marginata Trel.; A. americana ssp. protamericana Gentry; A. americana var. expansa (Jacobi) Gentry; A. americana var. oaxacensis Gentry (Catalogue of Life 2010; USDA-ARS 2010; ITIS 2010; Smith & Figueiredo 2007) Geographical range Native range: Mexico, southern United States Known introduced range: Argentina, Australia, Brazil, Canary Islands, China, Costa Rica, Croatia, Cyprus, Ecuador, Ethiopia, France, French Guiana, Galapagos Islands, Great Barrier Reef, Greece, Hawaii, India, Ile Amsterdam, Italy, Japan, Kenya, Kiribati, Lesotho, Malta, Macronesia, Malawi, Morocco, Netherlands, New Zealand, Oman, Pakistan, Peru, Philippines, Portugal, Romania, South Africa, Spain, Sri Lanka, Taiwan, Thailand, Tonga, Tunisia, Virgin Islands, Zimbabwe (Badano & Pugnaire 2004; USDA-ARS 2010) Introduction pathways to new locations For ornamental purposes: Landscape/fauna "improvement": A. americana is thought to be unintentionally introduced into sand dunes where it becomes invasive (Badano & Pugnaire 2004). Other: Garden waste - A. americana can reproduce vegetatively from fragments (Gordon et al. 2008). Local dispersal methods For ornamental purposes (local): Garden escape/garden waste: A. americana can reproduce vegetatively from fragments (Gordon et al. 2008). Wind dispersed: Seeds can be dispersed by wind (Henderson 2007). Management information Control of Agave americana is mainly achieved by using a combination of physical and chemical management techniques. Small plants are usually removed manually, while larger plants can be treated manually and/or with herbicide. Effective chemical treatments include cutting down leaves close to the ground and painting the stump immediately with herbicide and injection of herbicide. Follow up treatment may be necessary, especially for larger plants (Bickerton 2006; Ecoscape (Australia) Pty Ltd 2005; Weedbusters 2010). Reproduction Agave americana is monocarpic, i.e. it dies after fruiting. Bats, birds and insects are important pollinators of A. americana flowers. The black seeds produced have a high germination rate, though the majority of seedlings die 8-9 days post-germination. A. americana can also reproduce vegetatively from plant and stolon fragments, and via rhizomes. Bulbils are also produced in the floral stems, which can also give rise to daughter plants (Nobel 1988, Arizaga & Ezcurra 2002, in Badano & Pugnaire 2004; Gentry 1982, in Gordon et al. 2005). Reviewed by: Francisco I. Pugnaire, Estacion Experimental de Zonas Aridas, Consejo Superior de Investigaciones Cientificas Compiled by: IUCN SSC Invasive Species Specialist Group (ISSG) with support from the Auckland Regional Council (ARC) To contribute information, please contact Shyama Pagad. Last Modified: Tuesday, 18 January 2011