Do Sunflowers Close Up at Night

Do sunflowers close up at night? Or is it a common myth that lacks scientific backup? Let’s find out below!


As the day draws to a close, do sunflowers tend to go to a sweet sleep too, like nature’s own bedtime ritual? Read on to learn some scientific facts below!

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All About Sunflowers

Do Sunflowers Close Up at Night

Botanically known as Helianthus annuus, these towering beauties are part of the Asteraceae family that stands tall and proud, with robust stems holding large, disk-shaped flower heads. Each head bursts with thousands of tiny florets, all spiraling out from a central disk. The bright golden petals that ring this disk are like the sun’s own rays, which is how these flowers got their common name.

Do Sunflowers Close Up at Night

Sunflowers Close Up

Actually, it’s a bit of a myth that sunflowers close up at night.

What they do is something quite clever called heliotropism – tracking the sun’s path across the sky during the day. At sunset, they don’t close but simply stop their solar pursuit, often ending up facing east, where they last greeted the sun. From afar, their petals might appear a bit droopy at dusk, probably leading to the misconception that they close up. But in reality, they stay open, just taking a break from their daily sun-chasing routine.

Why Do Sunflowers Follow the Sun?

Sunflowers Follow the Sun 

Sunflowers display a remarkable behavior called heliotropism, where they actually track the sun’s journey across the sky. This movement is all thanks to a plant hormone named auxin, found in the sunflower’s stem tips. As the sun moves, auxin builds up on the stem’s shaded side, causing cells there to grow longer and bend the stem towards the sun. This clever mechanism ensures the flower head is always facing the light.

Young sunflower plants show this sun-following action most vividly, while older ones tend to do it less. This sun-chasing habit helps maximize photosynthesis, ensuring the flower gets ample sunlight all day. Interestingly, once sunflowers mature and start producing seeds, they usually stop moving and stay facing east. This position is great for seed production and helps in better dispersing them.

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