Sunflowers come in many shades and sizes and can bloom on a single stalk or on a multi-branched plant with many flower heads. These annual plants belong to the genus, Helianthus and as their name implies, thrive in full sun and grow best in fertile, moist, well-drained soil. Once established, however, they can tolerate dry conditions. Great for pollinators, Sunflowers can be used as mid to back-of-the-border plants and even make great thrillers in combination containers. They are also a must-have addition to the cutting garden.