Sunflowers

The sunflowers, singing out in brilliant color from the vegetable garden, are summer heat and light made into matter. The irony of their blooming is that now summer is on the wane: the days are noticeably cooler and shorter, the sun is lower and moon higher in the sky. It is as though they are giving a last grand gesture of brightness, to accompany the busy harvest season.

I grow a branching variety of sunflowers; rather than one large head on an enormously tall plant, these 6 or 7 foot tall plants have many 6 inch blooms, making a vivid display. I've always enjoyed seeing the development of the flower head in sunflowers, as it changes from flat to rounded form, so have photographed the procession for this post. Sunflowers are actually a composite flower, with the yellow "ray florets" around the center "disk florets". In the photo above you can see the spiral pattern of the disk florets, growing according to the golden ratio, which I wrote about in this blog post.




Over time the disk florets grow sexually active, from outer edge to inner. Pollen is released and flowers fertilized. The bees are very active around sunflowers, so there isn't much extra pollen; when I cut the flowers for a vase indoors, the pollen floats down to make a golden dust on the tabletop.




The flower head has become full and rounded and is now in the process of growing seed.




Here you can see the not fully matured black seed. I have learned in my online research that there are numbered stages of sunflower growth; it is, after all, an important food crop. You can see a clear explanation of this here (it's a pdf). The small seeds of my garden sunflowers are food for birds, who perch on the flowers and peck away at them. When my garden is finished for the season, I till a few of the mature sunflower heads where I would like them to grow next spring; I leave the remainder on top of the compost pile for the birds; I'm pleased to share my bounty with them.