Sunflower
An annual herb whose large, seemingly single flower head consists of many small flowers.
- Scientific name
- Helianthus annuus
- Family
- Asteraceae
- Other names
- Common sunflower
- Reviewed
A reference photograph of sunflower. Height and flower-head color and size can vary among cultivars.
Photo credit: böhringer friedrich
License: CC BY-SA 2.5
The photograph was resized and converted to JPEG.
Names and classification
Sunflower is an annual herb in the daisy family. This entry covers Helianthus annuus, including cultivated varieties differing in height, flower color and seed use.
Observable features
It has a rough stem and broad leaves; ray florets surround the disc florets at the center of the head. Treating the head as the equivalent of a single flower makes it easy to overlook the small individual flowers.
Distribution and habitat
Native to North America, it is grown in many countries as an ornamental and seed crop. In temperate regions it grows during the warm, frost-free season, so sowing and flowering times vary by location.
Ecology and life cycle
The head's small flowers provide resources for pollinating insects, and birds also use the ripe seeds. Distinguish movements of young plants from the orientation of mature flower heads when observing them.
Cultivation and care
Grow it in full sun without keeping the soil excessively wet. Provide support and room for tall cultivars to resist wind, and sow after the last local frost.
Observation and use precautions
Ornamental cultivation and production of edible seeds may involve different management. Do not treat garden seeds as equivalent to marketed food, or use this entry to decide whether similar wild plants can be eaten.