Asclepias syriaca Common Milkweed
This rosy butterfly weed is native to North America east of the Rocky Mountains. It grows wild along the roadsides and in open fields, is scrappy enough to compete with weeds and wild grasses, but it's anything but common. The fat clusters of soft pink blooms on 3' stems are impressive enough to inspire much fussing, but they don't need it.
Asclepias syriaca is hardy in all zones from 4-9, grows in crummy soil, full sun, will tolerate drought or whatever rainfall it gets. Plant it in out of the way where it won't tangle with your cutting garden. It's great in a meadow or a median strip. This sweetheart is tough.
Milkweeds are the ONLY host plants for Monarch caterpillars. They can't survive without Asclepias as a food source. Butterflies and hummingbirds sip the nectar while the caterpillars feed on the foliage.
Seeds are slow to germinate. Soak them overnight, then surface sow on moist soil and keep them warm. Once established, they'll take care of themselves.