Flowering cacti come in all shapes and sizes.  Some even change the way they grow as they get older.  For example, the silver ball cactus (Parodia scopa) begins life as a round, ball-shaped plant before growing upward into a column as years pass.  The cactus's bright yellow flowers also change.  When the silver ball cactus is young, it may only produce one flower, but in later years it can grow three or more.

Because growing cacti, especially those that flower, became so popular in the 21st century, many stores began selling different varieties.  However, cacti sold somewhere other than a greenhouse or nursery can be misleading to the buyer.  Some plants can be labeled as one species when they are actually another.  Stores also like to increase the plants' appeal by attaching colorful fake flowers to the tops.  These flowers are called strawflowers and can last many months when dried.  Some people believe them to be real because they may open or close depending on the moisture in the air.  When looked at closely, however, it is easy to spot the glue or pins holding the flowers to the cactus.

It can be difficult to get cacti to bloom without knowing how to properly care for them.  And even then, the flowers last only a day or two.  That is part of what makes cactus flowers so beautiful and sought-after.