Sunflower

Do sunflowers grow all over the world?

Why is the flower so big?
The sunflower wants to maximize the number of seeds it can make. The flower head is actually made up of 1,000 - 2,000 tiny flowers arranged in a specific pattern to maximize the number of flowers for that shape, like honey bee cells are hexagons because that is the best shape to fit in their hive. A sunflower relies on bees and other insects to help move pollen around the head of the flower so it can be pollinated. Butterflies and other insects often perch on an upturned sunflower head because its large, flat surface is inviting to insects searching for nectar. What other flowers in your garden give a flat surface for insects and what other insects would take advantage of this? Are there any more flowers in your garden that have big, flat heads (maybe not as big as sunflowers though!)?

Why are they black in the middle? Many flowers use visual cues to attract pollinators. The middle of the flower is darker than the surrounding pedals to help draw pollinators to the center where their pollen and nectar are. Flower shape and size also provide visual cues and structures that have co-evolved with pollinators. Can you think of other flowers that use contrasting colors to lure in pollinators?

What senses do the pollinators such as bees and butterflies use to find good flowers (ones with plenty of pollen and/or nectar)?

Why does it grow so tall? A sunflower’s goal is to try and make as many healthy seeds as possible and growing taller gives the plant more access to the sun. Sunflowers don't need to grow tall, there are a lot of species that are smaller and grow just fine. The taller they are means they are more likely to have greater access to more sunlight. Therefore it is just a natural instinct. Why do you think they call it a sunflower? What happens to the sunflower when the sun changes directions?