Ashy sunflower is a perennial sunflower usually appearing in colonies. Flowerheads are few, often a lemony yellow, to 3½ inches wide. The overlapping bracts beneath the flowerhead are many, narrow, and thin. July–October. Leaves sessile, stiff, densely gray-hairy, broadly ovate, opposite, with inconspicuous teeth.
Similar species: Of the 6 most widely distributed sunflowers in Missouri, 2 others have leaves with very short petioles. Stiff-haired sunflower (H. hirsutus) has fairly uniform lanceolate leaves, almost all opposite, with small teeth. The rough hairs make it feel like sandpaper. The flowerheads are all yellow; the rays often point upward. Prairie sunflower (H. pauciflorus) grows to 7 feet tall and has toothless, rough-hairy, mostly broadly lanceolate leaves that are green (not grayish). The disk florets are purple, the flowerheads few, but large.