Smooth cat's ear looks a lot like common cat's ear. However, the flowers are smaller and only open in the morning. It can germinate in the fall as well as in the spring. The leaf rosettes are relatively small when flowering, giving the plant a top-heavy appearance. Pigs and sheep pull the rosettes out of the bottom to eat. Pigs even dig up the roots, which explains the Dutch name 'glad biggenkruid' (smooth pigs herb). Smooth cat's ear grows in reasonably open, sunny places on dry, calcium-poor and nutrient-poor sandy soil. It has become a rare plant in the Netherlands. Smooth cat's ear grows in Central Europe and the Mediterranean Sea region. It has been imported into America.