Sunflower
Helianthus annuus
A tall, erect annual plant with coarse, hairy leaves and large, bright yellow flower heads featuring prominent dark central discs.
- Light
- Full sun, requiring six to eight hours of direct sunlight daily.
- Water
- Moderate watering requirements. Allow soil to dry slightly between waterings, and provide deep watering to encourage strong root systems.
- Growth
- An herbaceous annual with a single upright, unbranched or branched stem reaching heights between 3 and 10 feet with a rapid growth rate.
Care instructions
Provide full sun exposure for at least six to eight hours daily. Water deeply when the top few inches of soil become dry, ensuring good drainage. Apply a balanced fertilizer during the growing season to support robust stem and flower development.
Growing details
Sunlight
Full sun, requiring six to eight hours of direct sunlight daily.
Watering
Moderate watering requirements. Allow soil to dry slightly between waterings, and provide deep watering to encourage strong root systems.
Soil
Well-draining, fertile loamy or sandy soil with a neutral pH range between 6.0 and 7.5.
Hardiness zone
USDA hardiness zones 2 through 11 cultivated primarily as an annual.
Growth habit
An herbaceous annual with a single upright, unbranched or branched stem reaching heights between 3 and 10 feet with a rapid growth rate.
Bloom season
Blooms from mid-summer through early autumn, producing large composite flower heads with bright yellow ray florets and dark brown or black disc florets.
Propagation
Propagated easily from seeds sown directly into the soil after the last spring frost.
Common pests & issues
Susceptible to fungal leaf spots, powdery mildew, and stem rots if air circulation is poor or humidity is excessively high. Pests include aphids and caterpillars, which can be managed with insecticidal soaps.
Similar species
Jerusalem artichoke (Helianthus tuberosus), which features smaller multiple flower heads and perennial tubers.