There are many varieties of goldenrod, but my favorites are those that bloom in late summer or early fall, such as rough-stemmed goldenrod flowers (Solidago rugosa). Just as forsythia heralds spring with masses of yellow flowers, so the aptly named "goldenrod" ushers in the fall.
Native to North America, it is drought-tolerant, along with many other natives such as Coreopsis spp. For a pale yellow color, Moonbeam coreopsis is popular.
Goldenrod has several medicinal applications. Amy Jeanroy, About.com's Guide to Herb Gardens, mentions that goldenrod's uses include as an expectorant, for soothing inflamed tissues, and for respiratory and kidney issues.