Also known as as True Geranium, Hardy Geranium or Perennial Geranium, cranesbill can grow from 3 inches to 2 feet tall depending on the variety.  It prefers full shade or partial shade and well draining, moist soil.  Blooming times vary according to the variety you plant in shades of blue, purple, pink and white and the flowers will attract plenty of butterflies and bees.