Sunflower
Helianthus annuus
Other names: Common sunflower
Sunflowers are fast-growing annuals with broad, bright flower heads on tall stems. They range from knee-high pot varieties to giants over 10 ft (3 m) tall. They are among the easiest flowers to raise from seed, and the seeds feed both people and birds.
How to grow sunflower
Light
Grow in full sun, with six to eight hours of direct light. Young flower buds follow the sun across the sky. Mature heads settle facing east.
Watering
Keep the soil moist while seeds germinate. Once plants are established, water deeply once a week. Give extra water for three weeks before and after flowering for the largest heads.
Soil and feeding
Sunflowers grow in most soils and have long taproots, so loosen the ground deeply. They are heavy feeders. Mix compost into the bed before sowing.
Planting and pruning
Sow seeds directly outdoors after the last frost, 1 in (2.5 cm) deep and 6 in (15 cm) apart. Thin giant varieties to 2 ft (60 cm) apart. Stake tall types in windy gardens. Sow a new batch every two weeks for flowers until frost.
Propagation
Grow from seed each year. To save seed, let the back of the head turn brown, cut it with a length of stem and hang it in a dry, airy place.
Common problems
- Seeds or seedlings disappear
- Birds, squirrels and slugs. Cover the rows with netting until plants are 6 in (15 cm) tall.
- Tall stems topple
- Stake giant varieties and plant in a spot sheltered from wind.
- Lower leaves spotted or mildewed
- Common late in the season. Space plants well and water at the base.
Questions about sunflower
How long do sunflowers take to grow?
Most varieties flower 70 to 100 days after sowing.
Can I grow sunflowers in pots?
Yes. Choose dwarf varieties and a container at least 12 in (30 cm) deep.
Plant details
| Botanical name | Helianthus annuus |
|---|---|
| Family | Asteraceae |
| Native range | North America |
| Plant type | Annuals. Annual |
| Soil | Average, well-drained soil |
| Flower color | Yellow, orange, red |
- Attracts pollinators
- Good cut flower
- Edible
- Good for beginners
- Pet-safe
- North American native
