(Helianthus annus) Sunny yellow classic sunflowers are produced heavily on tall multi - branching plants. The flowers are 5-7 inches across and beautiful in late summer bouquets. These are also loved by birds, which will feed on seeds that develop from flowers left on the plant. The sunny yellow petals are a handsome contrast to the deep brown centers. Most/full sun - Annual - 7-8 feet - 25 seeds.