Shape of Things to Come

Oftentimes when we gaze at a garden and the aspects we admire most are the colors and the textures of the chosen plants.  But, what of the shape of the flower itself, shape plays an immensely important role in the design of any outdoor space.  If a gardener were planning a monochromatic look than the clever use of bevy of flower shapes would certainly enhance the overall outcome, rather than just having all bell-shaped flowers in blue.   That gets a little drab, quite the better-laid garden plan would be to have bowl-shaped blue flowers and globe-shaped blue flowers mixed with the bell-shaped blue flowers.  By sowing a wide assortment of flower shapes the eye will keep moving over the entire garden and by having repeating shapes the garden will have a sense of continuity. 

Why are flowers shaped the way they are?  Quite simply it is survival of the fittest; plants are vying for the attention of unsuspecting pollinators using their shape, color and scent to attract these transporters.  Oddly enough, in the beginning, flowers were not much to look at.  According to an essay by David Ditcher, a Professor at Florida Museum of Natural History, the fossils of the oldest known flowers, which were discovered by Chinese researchers, reveal that as of 145 million years ago, petals had not yet made an appearance.  These might have been wind-pollinated flowers and therefore they had no use for a showy look or perhaps they were just beginning to lure insects and were still in the process of developing special floral organs to advertise their wares. 

What is a flower advertising and to whom?  A flower is attempting to lure transporters to its sexual organs through the temptation of free food.   Ditcher’s essay states that showy flowers evolved approximately 125 million years ago.  The first petals were arranged spirally and would look similar to spokes on a wheel.  Then about 90 million years ago bees and other pollinators appeared and the flowers began to evolve beyond the spiral look into new shapes adapting to the new insects and birds.  These bees, moths, butterflies, birds, ants and other creatures get filled up with sweet, sugar-filled nectar that is protein and vitamin-rich.  By happenstance they touch pollen and fly or crawl or wiggle to the next plant, hence pollinating it.  Every physical characteristic of the flower from its petal design to the timing in which it blooms is all for the sake of reproduction. 

Dr. Lena Hileman, assistant professor of Ecology and Evolutionary Biology at the University of Kansas says, “The relationship between flowers and animal pollinators is ancient.  For the most part, it is the relationship between flowers and pollinators that has driven the evolution of flower shape.  Often, flowers are highly adapted to a specific type of pollinator.  For instance, flowers that are pollinated by hummingbirds tend to be red in color, have a long, tubular shaped corolla and provide copious amounts of nectar.”

Think about it, you would have to be full of perfume and candy too if you were rooted in one spot and the only way to roam and transport your genes was basically through bribery.  The flowers evolution is fascinating.  Consider the hammer orchid, whose flower evolved to resemble a female wasp to attract its pollinator, the male wasp.  Or the Foxglove, which has a pattern like the lights on an airport runway, directing the pollinator to the flowers nectar.  Flowers have had to adapt to the insects and birds that prefer them.  For instance, butterflies are attracted to flat, open surfaces like zinnias, certain bees like petals to serve as landing platforms like delphiniums.  Open, bowl-shaped flowers like poppies can be seen easily and are accessible for short-tongued pollinators, while tubular flowers cater to beaks and insects with long tongues.  Flowers that are bell-shaped provide shelter for honey and bumble bees that can feed while hanging upside down. 

Most flowers all have the common features in that they are designed solely for reproduction.  There are four whorls to a flower, 2 that are sterile and 2 that are fertile.  The petals (generally brightly colored) and the sepals (commonly thick and green located below the petals.  They cover and protect the petals when the bloom is in bud form) are the two sterile whorls.  The stamens (male part of the flower that has anther and filament), and the pistil (the female part that consists of stigma, style and ovary) are the two fertile whorls of the flower.  So, despite the complexity of every varying flower shape the basic elements of design are the same with the ultimate quest to survive and hopeful even thrive.

Hileman say’s of the research surrounding flower shapes, “Scientists are beginning to understand the genes that are important for shaping flower diversity.  In my lab we are interested in understanding how changes in gene expression and gene function establish various flower forms.  These are the underlying genetic changes on which selection, often through plant-pollinator interactions, may act.”

So, no longer will a honeysuckle simply be a honeysuckle, but rather a tubular-shaped hummingbird-attracting lure to propagate the spread and sprawl of honeysuckle as far as the eye can see. 

Flower Shapes:

• Daisies – provide a simple, natural look.
• Flatheads – the horizontal shape gives the eye a place to rest as well as an insect.
• Clusters – provide some weight to a garden design and provide many opportunities for a sweet snack for a visiting pollinator.
• Spikes – grab attention by adding height to the garden plan.
• Plumes – are playful with their fuzzy flowers, makes a good transition between spikes and flatheads.
• Globes – the unusual shapes makes them stand out as a great focal point for any garden.
• Trumpets & Cups – these are similar in shape but different in effect, trumpets are more of an attention-getter while cups are more casual in design.
• Fillers – a nice backdrop to fill in empty spaces.