Cactus flowers bloom in a rainbow of colors. The look of a cactus can be quite deceiving. Spiny, leafless desert cacti, mostly native to North and South America, transform into some of the most dazzling plants when in bloom. Belonging to the Cactaceae plant family, more than 1,000 different species of cacti exist, including those of the tropical variety that are indigenous to Brazil. (Read more: http://www.ehow.com/info_7988034_cactus-flowers.html#ixzz2mRPC36sQ)
Oxalis palmifrons hails from the deserts of South Africa. This oxalis looks like a giant green snowflake. Zone 7 - 10 Each symmetrical rosette has three dimensional, miniature palm-like leaves.In late fall it is topped with stalks of light pink flowers held just above the foliage. Oxalis palmifrons makes a great windowsill plant.
Cape Aloe or Bitter Aloe (Aloe ferox). Bloom in spring. Aloes are succulents, and this extra stored water in their tissues helps them deal with periods of drought. However, during unusually severe droughts, Cape Aloes and even some of our native plants will definitely need extra water in order for them to survive.