In 2014, a couple of my blooms were Polymerous, but I haven't seen any since then, so I'm not sure how common that is. Has it happened for anyone else in this thread?
My soil is very sandy and impoverished and the site is very hot and dry in July and August. I haven't gotten around to this area to give some compost or fertilizer, so my rate of increase is very low for this plant, but I do love its colour, so it is definitely a keeper.