Shapes and sizes vary greatly: the long raceme of white flowers on the vine Wisteria floribunda ‘Longissima Alba’*; ground-hugging sub-shrub Cotoneaster horizontalis with tiny leaves and coral red berries; colorful leaves of purple smoke bush, Cotinus coggygria ‘Velvet Cloak’.

 

Why do humans have thumbs? Why do cats have long tails? Why do many birds have colorful feathers? These physical features evolved because they serve invaluable purposes for each animal. Our thumbs give us precision grips. Feline tails help cats balance as they leap from one household precipice to the next. Male birds dress up to attract a mate.

Plants evolved helpful characteristics as well. Although they don’t have fingers, vines can grab on to surfaces. Some plants need to balance, often sending cantilevered branches in one direction to support growth in another. Showy flowers attract pollinators. We may capitalize on some of these traits—such as shape, form, and stature—for our plantings.

We seek naturally low, spreading plants for ground covers and flowering vines for colorful high points to our compositions. We might want long, dangling trumpet-shaped blossoms in one spot or clusters of glistening stars for another. Some flowers are flattopped and round; others grow on spikes held above their foliage. Spherical blossoms create masses of color, and floral spires can become energizing exclamation points.

Leaf form is another plant adaptation that we can look to for our designs. Small silvery leaves covered with hairs, powder, or wax evolved to preserve moisture in plants native to windy, dry climates. Broad leaves grew large to gather light in shady, humid habitats.

Once again, we are capitalizing on nature’s developments. Intricate, colorful flowers attract us, and they also demonstrate the concept of coevolution, since they developed right along with their pollinators: insects, birds, bats, etc. The blossoms lure their animal partners with the promise of sweet nectar, and in return, genetic material is carried to another member of the plant’s species.

One example of coevolution is the relationship between milkweed and monarch butterflies. Milkweed blossoms provide nectar for monarchs, and its leaves feed their larvae. As the caterpillars eat, they ingest a toxin in the plant sap that does not harm them, but makes the larvae unpalatable to predators. Birds learn to recognize the caterpillar’s yellow, white, and black bands as an announcement for “do not eat.”