Mammoth Sunflower 8-12 feet tall with 1 foot wide flowers! Annual that likes full sun-part shade 8-12' tall. A Striking Colorful Sunflowers in warm shades of orange and yellow. Blooms are strong-stemmed and 12" across, an excellent choice for cutflowers. Provide full sun and well-drained soils. Flowers from seed in 80-90 days Zones 3-10.