Cacti are firmly affixed in legend, Movieland imagery and our imaginations as icons of desert life. Whether tall and commanding like saguaro (Carnegiea gigantea) and organ pipe (Stenocereus thurberi), diminutive like pincushion (Mammillaria microcarpa) and hedgehog (Echinocereus engelmannii) or shrubby like prickly pears (Opuntia spp.) and chollas (Cylindropuntia spp.), their sturdy, often spiny stems coupled with breathtaking blooms represent the twin nature of deserts and stark beauty united with severe living conditions.
But these desert charmers are more diverse than simply tall saguaros gracing the Arizona sunset or little potted souvenirs. They offer an ease of care that make them enjoyable for all gardeners. Most cacti are arid-land species, coming from areas that have intense sunlight and heat, long spells without rain and bleak-looking, often rocky soils. They dominate the succulent plant family and are splendidly adapted to meet the challenges of their harsh environment. These adaptations define the parameters of their care.
And it all begins with their remarkable roots.
All cacti have a wide, spreading root system of countless fine, webbed roots that are responsible for taking up water and moisture. These roots generally radiate far from the plant – in tall or columnar cacti, they spread at least as far as the height of the plant – but they remain as close to the surface as possible. In most species, roots rarely go below 6 inches from the surface, and even in huge, columnar species like saguaro, they’re rarely more than 3 or 4 feet deep.
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