Classification

• To qualify as a barrel cactus, a cactus must be less than 10 times as tall as it is wide and be more than 5 inches in width. The cactus must also have vertical ribs running from the top to bottom, like the planks of a wood barrel. Specimens of barrel cacti include the fishhook (Ferocactus wislizenii), California barrel (Ferocactus cylindraceus) and many-headed (Echinocactus polycephalus).
  
  

Appearance

• Barrel cacti have sharp thorns or spines. These spines may be red in fishhook or California barrel cacti, or yellow or brown, as in the small Texas barrel cactus. Mature plants bear yellow, red or orange flowers during the summer months; the flowers grow only at the top of the plants, never along the sides.
  
  

Fun Facts

• Barrel cacti grow very slowly, so a four-year-old cactus could be only 3 inches tall by 2-1/2 inches wide. After 12 years of growth, they're mature enough to flower. Though slow growers, they can live up to 130 years. Fruit develops from the flowers and turns yellow when it's ripe. The fruit tastes bitter, but makes food for wildlife.
  
  

Range

• Barrel cacti grow naturally in the deserts of the southwestern United States and Mexico. The fishhook barrel cactus may be found in Arizona, Texas and New Mexico. Utah, Arizona and Nevada house the many-headed or cottontop cactus, which has yellow flowers. The California barrel cactus grows in California, Nevada and Utah. Gardeners in other regions can grow barrel cacti as houseplants.