Seeds from Helianthus salicifolius Willow-leaved Sunflower. Native Range: South central United States Features clusters of 2-2. 5″ wide sunflowers with bright yellow rays and dark brown center disks atop rigid, whitish-green stems typically growing 5 to 6′. Narrow, drooping, willow-like, pale green leaves 5-7″. Blooms from late summer to fall. The late season floral display of bright yellow sunflowers with brown centers makes this plant one of the most spectacular fall blooming plants. The stems will grow to over 10 feet in part sun, but only half this height in full sun. They respond well to a variety of moisture and soil conditions. Good cut flower. Zone: 4 to 9.