I've discovered that propagating Echinacea - Purple Coneflower - from root cuttings is a fairly easy task. Get out your shovel and dig out about half of your plant. I like to leave 50% in the soil to ensure the plant comes back well.
I then use a combination of my axe, and pruners to cut up the larger roots into two inch segments and plant them upright in potting soil-then water well.
I've found that different Echinacea varieties have different booming periods.
I remove the plants which bloom for a short time and keep the plants which bloom over an extended period of time. I've even found a variety which I call "Echinacea terrificalis" which blooms almost the entire summer season.