Where I live the average life span of a perennial is three years. Yes they come back year after year but not always forever. It is very important to divide short lived perennials here every three years to keep them going strong. Many long lived perennials are available so it pays to do a little planning when creating your garden beds. Some of the long lived perennials in my garden are iris, hydrangea, hosta, peonia, shasta daisy Becky, Russian sage, lambs ear, geranium, Japanese anenome, sedum autumn joy, blue salvia, sedum angelina, and daylily.
