Purple Coneflower… Echinacea purpurea...blooms heavily for many weeks in spring and summer.  Grows 36" tall xo 24" wide. Over the years we could only keep this coneflower in the garden for only a year or so then it would die away and we could never get the seeds to germinate.  We found these plants dry root in a bag at Walmart and have had them in the garden for several years.  We now have a number of plants as the seeds are viable and readily germinate.