What Causes Sunflowers to Follow the Sun?

Did you know that bees tend to land on sunflowers facing eastward rather than westward? Sunflowers are commonly associated with the autumn and harvest season and have been featured in some of the most famous paintings. But why do these plants have a constant connection with the sun? In this article, we’ll explore the reason why sunflowers follow the sun.

What is Heliotropism?

Young sunflowers will always face the sun, a phenomenon known as heliotropism. This is a plant’s response to sunlight that corresponds to its directional growth. Sunflowers are believed to participate in heliotropism due to an internal clock, similar to humans. This biological clock aids the plant in growing to its fullest and receiving the most energy possible.

What is the Complete Cycle of Heliotropism?

The movement of sunflowers is often referred to as heliotropism. At dawn, the sunflower head will be facing east, ready for the sun to rise. As the sun rises, the sunflower’s head begins to rise with it, and throughout the day, the head tracks the sun’s movement across the sky. When the sun sets in the west, the head finishes in this position, and overnight, it gradually returns to face east again.

How do Sunflowers Move?

During the day, a young sunflower plant tracks the sun for optimal growth, and the stem plays a vital role in this. The stem elongates to support the moving head, and in the morning, the east side of the stem expands, allowing the head to move west. At night, the west side of the stem elongates to allow the head to move back east.

Why do Young Sunflowers Follow the Sun?

Young sunflowers need to track the sun to receive the optimum energy to grow strong. This is known as photosynthesis, where leaves collect the sun’s rays and convert them into energy and food for the plant. A lack of sun will leave a plant weak. Tests have shown that sunflowers with restricted stem movement have less leaf area and decreased biomass.

Do Mature Sunflowers Follow the Sun?

Mature sunflowers stop following the sun. This is primarily because their growth slows down as they reach their peak. As they age, the flower’s circadian clock reacts positively to early morning sun rays instead of afternoon sun.

Sunflowers adjust their internal clock to focus on adequate sunlight, resulting in a stunt in their growth. Another reason for sunflowers to face east is to attract bees, as they are more likely to land on flowers facing east than west. This is because the flowers become warmer quicker from the morning sunlight, and bees prefer warmer blossoms. Sunflowers facing east benefit from quicker blooming and increased pollen production, resulting in larger and heavier seeds. Sunflowers have a circadian rhythm and continue to face east in their mature age to help the bees pollinate. Their vibrant yellow petals add beauty to any landscape and have fascinated humans for years due to their human-like movements in correlation to the sun.


1. What is the reason behind sunflowers facing the sun?

Sunflowers follow the movement of the sun because they are heliotropic plants. During the day, they face east to absorb the maximum amount of sunlight for photosynthesis and growth. As the sun sets, they face west and then turn back to the east to face the sun again in the morning.

2. Do all sunflowers face the sun?

Although most sunflowers are heliotropic, there are some varieties that do not exhibit this behavior. These sunflowers have been bred to have a more upright posture, making them more suitable for cut flowers or ornamental purposes.

3. Is there any benefit to sunflowers facing the sun?

Yes, there are several benefits to sunflowers facing the sun. First, this behavior allows them to absorb the maximum amount of sunlight for photosynthesis, which is essential for their growth and development. Additionally, facing the sun helps the flowers stay warm, which can help them attract pollinators and increase their chances of reproductive success.

4. Can sunflowers still grow if they don’t face the sun?

Yes, sunflowers can still grow even if they don’t face the sun. However, they may not grow as tall or produce as many flowers as those that do exhibit heliotropism.

5. What happens to sunflowers on cloudy days?

On cloudy days, sunflowers may not face the sun as strongly as they do on sunny days. However, they will still exhibit some degree of heliotropism, and they will continue to grow and develop normally.

6. Do all parts of the sunflower plant face the sun?

No, only the flower heads of sunflowers exhibit heliotropism. The leaves and stems of the plant do not follow the movement of the sun.

7. Are sunflowers the only plants that face the sun?

No, sunflowers are not the only plants that exhibit heliotropism. Other plants, such as corn and marigolds, also follow the movement of the sun to some degree.

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