Once known by the Latin genus and species name of Solidago rigida, stiff goldenrod (Oligoneuron rigidum) has some of the largest individual flowers of the genus. This native perennial grows to 5 feet tall, with a spread of 2½ feet. Each of its flat-topped inflorescences (a cluster of flowers arranged on a stem) are frequented by butterflies and, once the seeds are ripe, birds. This plant thrives in full sun and average soil. The gray-green leaves of summer age to a dusky rose color in autumn. Gardeners may want to deadhead the flowers to discourage this plant from becoming weedy. Stiff goldenrod is free of major insect and disease problems, and is not a favorite of deer.