Purple Coneflowers start blooming in mid-June and continue until frost, provided the dead flower stems are removed.  Mine grow 2¾'-3' tall, and have very strong stems.  They are very easy to grow from seed, and are a good butterfly plant.  Goldfinches love to eat the seeds, but won't visit as often if the flowers are deadheaded.  Purple Coneflowers are often said to be drought tolerant.  Don't believe it!  They wilt terribly at the first sign of hot weather.  In my garden, the flower petals are devoured by earwigs and Asiatic Garden Beetles.  Only three of the plants pictured at left are the variety "Bright Star."  All twelve of my coneflowers are now Bright Star plants, including the one pictured below.