This is another bloom that my sister in law gave me years ago from her country garden. I planted it in my small garden in town that was mostly clay. When we moved to the country I brought this May - June Bloomer and planted it in mostly sunny and somewhat sandy soil. She is doing well and I have been able to divide it twice now in the past six years. I know it as 'BUTTON FLOWER'. Any ideas what this pretty bloomer is really named?