Lessons from Sunflowers

Sunflowers are by far one of my favorite garden flowers. They are fairly easy to grow, are big and bright and live up to their sunny name. They attract bees and birds. Sunflowers are also a great plant to grow with children.

Not only are sunflowers a lovely addition to the garden, but they can also be the launching point for several different science and math lessons. From types of flower and flower parts to biological phenomena like tropism, and natural math like the Fibonacci sequence, a sunflower can teach you a lot, let's see what there is to learn!

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Composite flowers

Small flowers of the inflorescence are beginning to open. ©SBF

Sunflowers are composite flowers. If you look carefully at the center of a sunflower you may have noticed that there are a bunch of tiny flowers there. This clump of tiny flowers is called an inflorescence, or a cluster of flowers that make up one larger flower.

Many composite flowers have 2 types of flower parts. There are the petals that form what looks like rays of sun on a sunflower, then the smaller flowers in the inflorescence. You are probably familiar with many other members of this group of flowers- Dandelions, Black-eyed Susans, Asters and Hawkweed. 

Phototropism

You can observe phototropism in sunflower plants. Phototropism is the concept of a plant growing towards light. There are many tropisms, or plant movements to external stimuli. You'll notice this with your houseplants that lean toward the window and in your garden they learn toward the sun. 

Can you tell which side of the garden is shaded by trees and which is open to the sun?

Leaning sunflowers! ©SBF 2015

From seed to adult plant the sunflower grows towards the light. Here is a time lapse video of this process:

If you are interested in the idea of plants in motion, you'll want to check out Roger Hangartner's videos at his website, Plants in Motion. They are fascinating! See some sunflowers in motion here.

I also explored this concept earlier in the summer with the tendrils of my cucumber vines.

Sunflower Math!

The spiraling shapes in the seeds of a sunflower follow the Fibonacci sequence.

Fibonacci in the center of a sunflower! ©SBF 2015

You can find the Fibonacci sequence, 1, 1, 2, 3, 5, 8, 13, where each new number is the sum of the previous 2, all over the garden and in nature. I explored this concept in greater depth earlier in the summer. Go on a math scavenger hunt in the garden by following this link. 

Besides teaching us lessons in science and math, sunflowers are a cheery addition to any garden space!