how to prorogate coneflower. I garden in zone 8A 

Best method is by dividing the roots. Easiest method is by spreading the seeds-direct sow into the soil-just make sure the flowers are blacken and dried out. Cutting method is good to but hard depending on your zone and medium. Mother nature self seed coneflowers all the time so don't stress about it. Have fun and I wish you all the best. I generally just buy 1 plant and then root more if I like the plant.