Grow giants in your garden! Amazing tall sunflowers for wildlife and humans. Stalks average 9' tall and may reach a height of 10' or more. Heads average 11" across, with some reaching 14" or more when plants are well grown. Black seeds. Space 18 inches apart. Packet (7g) has about 70 seeds. Annual, 85 days. Family: Asteraceae (Daisy).