Every gardener dreams of the ideal plant— one that has interesting structure and beautiful flowers, thrives on neglect, draws gasps of admiration from the neighbors, and comes in enough varieties to fascinate for a lifetime. The ideal plant is, in short, a succulent.
Succulents are like self-made people-successful in spite of adversity, overcoming the odds. These stubborn individualists of the plant world have adapted to great climatic changes over millions of years. The methods of survival that have evolved are unique to succulents and curious by any standard.
All succulents store water in their leaves, stems, or both. This is what makes them succulents and is itself an evolutionary development. But the way in which they store or obtain the water varies, the variations being dictated by the climatic conditions of their native habitat. Some succulents developed disproportionately thick rootstocks to store moisture and nourishment for periods of drought and searing sun. Where a previously dry or moderately dry habitat gradually became wetter, many succulents evolved into tree-living plants called epiphytes; they began to use their roots for gripping trees to adapt to a dryer microclimate rather than drawing nourishment from the damp and inhospitable ground. Their leaves absorbed moisture from the air. Still other succulents adapted to rocky or frigid environments.
Not all succulents are arid-area types, such as the desert cacti. Some grow in tropical climates where there are long dry seasons, followed by short but intense rainy seasons, which in turn are followed by periods when the ground becomes increasingly dry but the atmosphere remains humid These climates produce cacti such as the pencil cactus (Rhipsalis species) and the orchid cactus (Epiphyllum species). The lily family is also represented by succulents such as the well-known aloes (Aloe barbadensis, popular for treating burns), the elephant's foot tree or ponytail (Beaucarnea recurvata) from Mexico, and the mother-in-law's tongue (Sansevieria species).
If the key to a succulent's success could be summed up in a brief descrip-tion, it would be "water thrifty" Succulents have mastered the art of water conservation. By reducing their leaf surface to minimize water loss from transpiration (the plant equivalent of breathing and perspiration), and by storing water in their stems or leaves, succulents can control both the amount of water they need and the amount they use.
There are other water-thrifty plants besides succulents. The desert wildflowers that make such a brilliant display immediately following the seasonal rains have adapted to a limited water supply by establishing a pattern of a brief growing season followed by a long dormancy. Succulents can indeed be considered the camels of the plant kingdom.