What Is a Helianthus Annuus?

The tallest sunflowers shoot up to 15 feet high.

The common sunflower (Helianthus annuus) is an annual plant. It is native to most of North America and some European countries, flourishes in dry open areas and prairies, and is sometimes considered and treated as a weed in cultivated areas.

Features

Sunflowers may grow to be 15 feet tall. Coarse, hairy stems contain oval or heart-shaped leaves and uphold a large flower head. This 5-inch wide flower head contains thousands of florets surrounded by yellow ray flowers.

Care

Sunflowers favor well-drained, moist soil with a neutral to slightly alkaline pH. They grow throughout summer, preferring full sunlight, and can tolerate dry periods.

Interesting Facts

The flower head turns to face the sun as the day progresses, beginning the day looking eastward, ending the day facing the sunset, and turning again during the night to prepare for sunrise.

The sunflower is the official state flower of Kansas.

Most of the world's sunflower oil comes from Russia.

References

• Floridata: Helianthus annuus
• University of Wisconsin-La Crosse: Helianthus annuus
• Lady Bird Johnson Wildflower Center: Helianthus annuus