About Helianthus schweinitzii Torr. & A.Gray
Schweinitz's sunflower, Helianthus schweinitzii Torr. & A.Gray, grows between 3 and 13 feet (1 to 4 meters) tall, with an average height around 6.5 feet, and can occasionally reach heights of 16 feet. This plant produces tubers and rhizomes underground. Its stems are purple, usually solitary, and branch only at or above the middle section of the stem. Its leaves are thick and stiff, and tend to droop toward their ends. Schweinitz's sunflower is a perennial plant that blooms for roughly two to three weeks in early October. It spreads via seed dispersal, and its seeds do not require a dormant period. A single plant typically produces 3 to 6 yellow flower heads. Each head holds 8 to 15 ray florets surrounding 40 or more disc florets. This sunflower is only found in the Piedmont region of North and South Carolina. It generally grows in shallow, low-quality, clayey, and/or rocky soils. It grows best in full to partial sun. Most of its populations grow near power line right-of-ways or roadsides. In 2003, 80% of all known populations were located near railways, utility roads, and roadsides. Today, 13 known populations of Schweinitz's sunflower exist in North Carolina.
