Family Jewels Gomphocarpus physocarpus
This lovely white milkweed grows 6' tall. Clusters of fragrant blooms grow on long stems (they make great cut flowers), drawing butterflies to the plant, and they turn into some of the weirdest seedpods in creation.
Swan Plant is native to Africa. It's perennial in zones 9-11, a fine annual anywhere as it bloom in only 7 weeks from seed, and it reseeds enthusiastically. Leave it alone and you'll soon have a chorus line of graceful blooms. Remove the pods if you don't want a spread.
About those pods. Translucent lime green hairy balloons grow in clusters on long stems. Even cooler than the flowers for arrangements, they inspire giggles and adolescent humor. "Hairy Balls" , "Family Jewels", whatever. Grow it for flowers, grow it for giggles, most certainly grow it for the butterflies.