Sunflowers (Helianthus) comprise of 70 species that are annual plants with big, daisy-like flower faces of bright yellow petals (and occasionally red) and brown centres that ripen into heavy heads filled with seeds.
Sunflowers can grow to a height of 300cm or more. During growth, sunflowers tilt during the day to face the sun but stop once they begin blooming. This tracking of the sun in young sunflower heads is called heliotropism. By the time they are mature, sunflowers generally face east.
Most sunflowers are remarkably tough and easy to grow as long as the soil is not waterlogged. Most are heat and drought tolerant. They make excellent cut flowers and many are attractive to bees and birds.
Sunflowers grow best in locations with direct sunlight (6 to 8 hours per day); they prefer long, hot summers to flower well. Sunflowers are heavy feeders so the soil needs to be nutrient-rich with organic matter or composted (aged) manure. Or, work in a slow release granular fertilizer 8 inches deep into your soil.