Please watch this video I recorded of a Giant Swallowtail on our first year Purple Coneflower plants.
I started these Purple Coneflowers from seed for the first time in March. Purple Coneflowers are among the best perennials for attracting butterflies such as Monarchs, Swallowtails, Gulf Fritillaries, and Painted Ladies. Hummingbirds will come, but not only for nectar, but the small insects the blossoms will attract. Perhaps the best feature is the blooms will remain colorful for a very long time so it can be enjoyed for many days.
I obtained my coneflower seed in the summer of 2010 when we vacationed in Indiana to visit family and pickup my son from Ohio. My grandma had a few dried seed pods on her coneflower plants so I took a couple home with me. The seed can be difficult to actually harvest because of the prickly pods shown below. But fortunately the coneflower is relatively easy to sprout and grow from seed. Plants will often self-seed in gardens too. An ideal location is full sun with well-drained soil, but they will grow in partial sun.