Most late summer wildflowers are indigenous to prairies, open woodlands or the edges of woodlands where they are not shaded by the forest canopy. Most of these prairie wildflowers have thick stems and thin leaves, which reduces their exposure to drying winds. The roots of perennial wildflowers can grow 10 feet below the surface searching for moisture.
With the same coloration as the black-eyed Susan, the petals of yellow coneflowers (Ratibida pinnata) droop downward and are longer and thinner than the petals of black-eyed Susans. Blooming from June to September, the center disk flowers start out gray and turn brown as the outer ray petals open and the flower ages. Yellow coneflowers are native to the American prairie and grow over 3-feet tall. They are found along roadsides, railroad tracks, prairies and at the edges of woodlands.
Native to the Great Plains of the United States, tall thistle (Cirsium altissimum) grows from 3 to 8 feet high, depending on growing conditions. Light purple flowers made up of a mass of tubular florets grow at the ends of its branches. The flowers are 2 inches long and 2 inches wide with a cup-like series of bristly bracts beneath the florets. Tall thistle blooms in August and September in open lowlands, fields, ditches and near woods.
Native to North America, stiff goldenrod (Solidago rigida) blooms from August through October. Its many tiny golden flowers give it a fluffy appearance on plants growing over 3 feet high. Their gray-green leaves and stems have gray hairs. Stiff goldenrod grows in partial to full sun in dry to moderately dry sandy soils in prairies and alongside woodland areas.