Why does sunflower always face towards the Sun?

Bright, big yellow petals, tall green stems. Sunflowers are cheery, warm, and inviting as the summer sun. Surely a bunch of this vibrant flower can chase your gloomy day away. Sunflowers remain a well-loved subject for paintings, photographs, and even for itsy-bitsy accessories.

Sunflowers come in many varieties. From small to very large and yellow to red petals, this stunning, crowd-favorite flower is more than just a pretty face. It is also rich in history and meaning. Different cultures across the world believe it means anything from positivity and strength to admiration and beauty.

Chinese believe sunflowers bring good luck and happiness, which is why the flower is the perfect gift during graduations and the start of a new business. Sunflowers also symbolize loyalty, admiration, and longevity. (click here for more details)

History says that sunflower was a common crop among American Indian tribes throughout North America. According to some evidence, the plant was grown in present-day Arizona and New Mexico around 3000 BC. Archaeologists believe that sunflower may have been cultivated before corn.

The American Indian tribes widely used sunflower both as a valuable food source and non-food applications. Sunflower seeds are ground or pounded into flour for cakes, mush, or bread. Some mixed the seeds with beans, squash, and corn. The seed was also cracked and eaten as a snack. Moreover, sunflower oil extracted from the seeds is used in making bread.

Sunflower is also widely known for its non-food uses such as purple dye for textiles, body painting, and other decorations. Parts of the plant are also used in treating snake bites and body ointments. Sunflower oil was applied on the skin and hair while the dried stalk was used as a building material. (click here for more details)

Sunflowers are fascinating little wonders of nature. We are fascinated with them as they are with the sun. Maybe it has a mind of its own as it faces the sun rising in the east and follows it across the sky until it sets in the west. Why does this happen? Are sunflowers attracted by the sun, or they just wanted to get tanned?

Let me tell you a tale. The ancient Greeks believed that sunflowers faced towards the sun because the nymph Clytie adored Apollo, the god of the sun. At first, he loved her too but later turned her affections towards another nymph. In her jealous rage, Clytie told the other nymph’s father, and the nymph was buried alive as punishment. The outraged Apollo turned Clytie into a sunflower, but her love for him was so strong that she watched him move across the sky every single day – just as sunflowers follow the sun.

Enough of this myth. Now, let’s talk about Science. The scientific name for sunflower is Helianthus, from the Greek words “helios,” which means sun, and “Anthus,” flower.  The unique phenomenon of sunflowers following the sun across the sky is called heliotropism. This is mostly observed in young flowerheads and generally stops once the flower starts to bloom. (click here for more details)

Just like humans, sunflowers also have an internal biological clock, known as the circadian rhythm. As the circadian rhythm creates several physiological and chemical changes in the body, so does it allows a plant to respond to changes in roughly 24-hour cycles.

According to an article in a journal Science (2016), when the sun starts moving in the sky from east to west, the east side of the stem of the sunflower plant grows faster than the west side. Due to this unequal growth on either side, the flower tends to bend in the sun’s direction.

Likewise, when the sun finally sets, the growth on the west side of the stem is higher than that of the east. As a result, the stem bends east, that is, the direction where the sun would rise again the next day.

The apparent reason for the young sunflower following the sun would be to maximize photosynthesis. Continuously facing the sun also helps the flowers to heat up quickly, giving them a clear advantage in pollination as warm flowers attract insects. Thus, it is the sunflower’s best interest always to face the sun in terms of reproduction.

True to its name, the sunflower reflects many of the sun’s positive characteristics. And it’s not surprising that people enjoy basking in its warming glow so much.