The soft, bluish-green cast of this perennial’s foliage and stems provide an attractive contrast to the cheerful yellow flower heads. The hair-clad foliage and its color give rise to several common names--ashy sunflower, downy sunflower, and hairy sunflower--and the specific epithet, mollis, means “soft.” It grows 2 to 4 feet tall and blooms mid to late summer in full sun and drier soils. As an open-land species, it needs at least six hours of sun to thrive, but it will tolerate light shade. It does best in well-drained and medium-dry soils that contain sand, rock, or clay. It performs best in poor soils, becoming weak and bushy in very rich soils.
Downy sunflower is native to the eastern and central United States, and it’s a threatened species in Ohio. It’s easily distinguished from other sunflowers by its heavy covering of hairs; broadly oval, clasping leaves; and greater number of ray florets in the compound flowers. Sunflowers have two types of flowers: ray flowers, which look like petals, and tiny disk flowers in the center of the flower head. Each five-petaled disk flower eventually gives way to a single seed at its base. Goldfinches are often seen eating the seeds directly from the flower heads. Native Americans domesticated the flower into a single-headed plant and used its seeds for food.
Downy sunflower is striking when massed and allowed to spread by rhizomes and self-seeding to form colonies. It forms broad clumps that are best suited for informal gardens and naturalized areas. The root system of Helianthus emits allelopathic chemicals that inhibit the growth of other plants, making it helpful in controlling weeds and also in establishing itself.
Native habitats include prairies, grasslands, roadsides, savannas, woodlands, old fields, and forest openings. In addition to massing in large areas, ashy sunflower does well in borders, cottage gardens, bird and butterfly gardens, and wildflower or native plant gardens.
Grows 2-4’ tall.
Prefers full sun and tolerates light shade.
Prefers dry to medium soils, including average, sandy, rocky, and soils that contain some clay.
Flower heads bloom June-September and are 3-5” across with 15-25 deeply veined ray flowers about 2” long. Heads are generally borne singly on the upper stems. The center disk is initially brown due to the bracts, turning yellow as the disk flowers bloom.
Opposite leaves are 2-5” long and widest near the base. Margins are smooth or bluntly toothed. Stem is branchless except for the flowering stems at the top.
Sunflowers are a keystone plant, hosting 76 species of Lepidoptera larvae, including the gorgone checkerspot butterfly and white-marked tussock moth. Twelve specialist species can only feed on Helianthus, including the frothy and banded sunflower moths (all four pictured here in order of their listing, preceded by their caterpillars when available). An additional feeder, sunflower head-clipping weevil, may cause flower heads to droop and fall off. Sunflowers are primarily pollinated by bees and are a popular late-season source of pollen for bumble, mining, leafcutting, green metallic, cuckoo, and other halictid bees. Butterflies and bee flies also visit the flowers.
At least 20 species of gamebirds and songbirds devour the seeds in autumn and winter. Gophers, rabbits, deer, and squirrels also feed on the foliage and other plant parts.
Medicinal, Edible, and Other Uses:
The leaf petioles, seeds, and flowers are used as an expectorant, diuretic, and astringent. Tea made from the leaves may help to reduce fever, and a poultice of leaves may be applied to sores, bug bites, and swellings.
The leaf petioles, seeds, and flowers are edible. The seeds can be pressed to make oil that has a high Vitamin E content.
Native Americans used the plant as a dye and for building material.
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