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Why does a sunflower move throughout the day? The flower’s face, or blossom, follows the sun as it moves across the sky. This happens because the stem below the blossom grows unevenly. The west side of the stem grows fast in the morning. As a result, the blossom turns towards the sun in the east. The east side of the stem starts growing faster than the west during the afternoon. So, by sunset, the flower is facing the sun in the west.