Even though Vernonia noveboracensis (New York Ironweed), a native wildflower to the eastern United States, can be found in most cow pastures (for some reason, untouched), I have grown it in my garden for about 20 years.  A member of the Aster family, its 3-7 foot stalks support flat-topped clusters of brilliant purple/red flowers in late summer when not a lot else is blooming.  Its color is what I like best - one not found all that often in the flower world.  And even though there are those who may not consider Vernonia noveboracensis garden worthy, I disagree; in fact, I'm hard pressed to think of many flowers that aren't garden worthy.  I agree with Ralph Waldo Emerson who said that a weed is a plant whose virtues we have not yet discovered.  Vernonia blooms around the same time as Goldenrod, and nothing is lovelier than the two together in a great big vase.  Ironweed prefers sun in Zones 4-8.  Quarts.