Acres of sunflowers line a portion of Route 78 North, near Havana, Illinois. Helianthus is the scientific name of sunflower; helia meaning sun and anthus meaning flower. They are the symbol of faith, loyalty and adoration. They follow the movement of the sun across the sky from east to west and the process is known as heliotropism. To grow, they need full sun, at least six hours every day. Once a sunflower blooms, they last around 20 days.