Cacti come in hundreds of different shapes and sizes and can thrive in a wide range of conditions beyond their normal desert setting. Cacti have been around for more than 30 million years, are easy to grow and are a source of food in many countries.
There are more than 2,000 species of cacti that range in size from 1 centimeter to 55 feet. The largest species is the tree-like saguaro with its familiar curved arms and the smallest is the Blossfeldia liliputiana. Cacti are durable and live anywhere from 25 to 300 years depending on the species and evolved between 30 million and 40 million years ago. In addition to the traditional desert cacti with their familiar spines, there are also fleshy forest cacti.
Where they Grow
Cacti are succulents that thrive in places most plants won't grow including deserts, semi-deserts and dry steppes. The cacti spines are actually modified leaves designed to defend the plants against water seeking animals and to shade the surface of the plant and reduce evaporation. Most cacti have long dormant periods and very short growing periods that coincide with the rainy season.
Unlike most plants, cacti are not pollinated by bees. Given the arid climate most cacti grow in, the job of pollination is handled primarily by insects, hummingbirds and even bats in some cases. Most cactus flowers bloom in the spring and for a very short period, in some cases only a few hours.
Cacti have many commercial uses. The primary business is done by nurseries that sell ornamental cacti for gardens. People in desert communities often use rows of barrel cacti as natural barriers and fences. The flesh of many cacti is edible and has long been used as an inexpensive source of food. Some species, most notably the cacti that grow "prickly pears," produce fruit that's considered a delicacy in Mexico and some Mediterranean countries.
Cacti gardens are popular because they are easy to maintain. To grow desert cacti, place them in an area where they will get plenty of sun and water them only during the spring and summer. For forest cacti, water them as you would any regular plant. If you need to fertilize them, most garden centers stock special fertilizer for desert cacti. Forest cacti do well with any regular fertilizer.