The Arid House contains plants from around the world that are adapted to survive in regions that receive very little precipitation; these arid regions are called deserts if they receive less than 10 inches of rainfall annually.

Capturing, storing, and conserving water is essential in arid environments. A succulent is any plant that can store water in its stems, roots, or leaves. All cacti are succulents, but not all succulents are cacti. Other examples of succulents include euphorbias, agaves, and aloes. These plants have evolved a variety of ways to survive in extreme heat with little water, such as capturing water with extensive root systems, storing water in their fleshy tissues, and by reducing water loss through thick, waxy stems or leaves.

The Arid House plant collection, with about 10,000 plants representing 2,500 accessions, contains a substantial number of the most biologically and scientifically valuable plants in the Garden, including many living “type” specimens—the exemplar individual a taxonomist uses to describe a new species. Other specimens belong to species that are now extinct in the wild, and are therefore irreplaceable.

Glass House Design

The Arid House, which opened in the spring of 2002, is the first automatically climate-controlled glass house in the Garden. It replaced the Desert/Rainforest House that had served the Garden for more than 60 years. As you walk through the Arid House you may notice the noise of the computer-controlled adjustments of vents, fans, and/or shade cloths used to maintain the proper environment for the collection. Fans circulate the air for cooling or heating, while roof vents open and close to moderate the temperature. The shade cloths extend over the collection to protect plants from being scorched on sunny days and retract on foggy days.