All the species included in this collection are native to arid regions of the American continent and are capable of withstanding minimum winter temperatures of at least –15 °C.

In designing this collection, substrates of distinctive colours were chosen to differentiate each of the three beds. In the cactus bed, the black gravel and rocks placed between the plants serve a dual purpose: decorative and protective, as the dark colour of the substrate allows the soil to warm up during the day through solar radiation. At night, the absorbed heat is released slowly, which is essential to counteract the cold winter nights of La Mancha.

Cacti (family Cactaceae). Cacti are succulent plants (they store water in their tissues) native to the Americas. They generally possess spines, which are the result of the evolutionary reduction of leaves to minimise transpiration and protect the plants from herbivores. This collection includes species from various genera such as Echinopsis, Carnegiea, Cleistocactus, Opuntia and Ferocactus, displaying a wide range of forms: columnar, globular and branched into phylloclades (the pads of prickly pears; Opuntia). A dark volcanic rock substrate has been selected to enhance heat retention during colder periods.

Agaves and yuccas (family Asparagaceae). These two genera are of great cultural and economic importance in tropical, subtropical and arid regions of the Americas, as they provide fibres, paper, nails, needles and spirits such as tequila and mezcal. Species on display include Agave parryi, A. victoriae-reginae and A. nigra, among others. Their striking flowering occurs through the development of a tall flowering stalk, after which the plant dies.

For the genus Yucca—plants native to North and Central America, with sword-shaped leaves arranged in basal rosettes and white flowers—species such as Yucca thompsoniana, Y. torreyi, Y. aloifolia, Y. neomexicana and Y. rostrata have been planted.