I had an eye opening experience yesterday.
Every day I sit by a huge window overlooking my back garden to drink my morning tea. While I sat enjoying the view, a bevy of butterflies swooped into the yard to begin their daily feeding frenzy. They come almost every morning at about the same time for an extended meal and then pop in and out the rest of the day.
As I watched them, something clicked in my brain; I realized that they were showing definite preferences for the pure native blooms over both the cultivars and the introduced, non-native species. They landed on the pure natives more often and seemed to stay longer.
I’ve known for a while now that native plants are nutritionally better suited to our precious pollinators than introduced species. Multiple research studies have confirmed that. What I hadn’t really processed though, was the reality of the impact that human intervention can have on native plants which are the food sources for pollinators.
Humans have been “breeding” plant species for thousands of years. History shows that Mesoamericans domesticated corn by cross breeding as early as 8000 BC. Babylonians hand pollinated date palms to produce a bigger crop. The Chinese were proficient in grafting fruit trees.
By the 1700, plant breeding was a popular activity, although the science behind it was relatively unexplored. In the 1860’s, Gregor Mendel began to unravel the role of genetics in manipulating the characteristics of plants. His work, and the study of many after him, opened the door to the myriad of plant choices gardeners have today.
Globally, plant breeding today is close to a 30 billion dollar industry, with the US share standing in excess of 18 billion dollars. While most of those dollars are directed towards food crops, over 4 billion dollars fund work on ornamental plants.
We know that breeders strive to produce plants that are superior in garden performance and unique in appearance. They are searching for disease and pest resistance, drought tolerance, improved vigor and form, brighter or more diverse colors, increased flowering to name just a few of their many goals.
A trip to your local garden center shows how much they have already achieved. Racks are burgeoning with seductive choices— even in the “Native” section. And that’s where we need to be cautious. Not all “Natives” are completely native: many have never grown in the wild at all. They are cultivars (nativars), or the result of “selective breeding by humans” (Piedmont master Gardeners) and are typically developed for purely aesthetic reasons.
In the wild, the morphology of a plant, its physical form and structure, has evolved to benefit specific pollinators. The shape of the bloom and the large amount of nectar one species of cardinal flower produces,
Lobelia cardinalis, meets the high energy needs of hummingbirds, but because of that shape, bumblebees can’t access the nectar. Lobelia siphilitica, 
on the other hand, is suited to the rounded shape of the bumblebee. It also produces less nectar, which is more appropriate for bumblebees.
Research has also found that the more changes made to a native plant’s features, the 
less likely it is to provide adequate nutrition to its intended pollinators. Sometimes changes in color make a difference. Fewer pollinators seem to visit pink asters as compared to the straight species of New England asters, which are blue. 
Blooms whose shapes are changed, especially from single-petaled to double petaled tend to have fewer pollinator visits simply because the nectar is more difficult to access. The standard Echinacea purpurea has been shown to attract significantly more pollinators than the cultivar “Pink Double Delight”. Cultivars developed to achieve a shorter, more manageable size for a residential garden – think Joe Pye weed and its variations – have fewer visitors because they ultimately have fewer blooms per plant.
Finally, widespread use of nativars/cultivars has the potential of losing genetic diversity of the species. Cultivar, the original term is shorthand for the phrase “cultivated variety.” In other words, these plants are developed for specific characteristics like bloom or foliage color. Usually, parent plants are cross pollinated to produce a specific characteristic in the offspring. Then stem cuttings, grafts or tissue cultures are taken to produce clones, or identical plants sharing the exact, same genetic make-up. Since there is no genetic diversity, plants cannot naturally adapt to changing environmental needs. Eventually, weakened plants can disappear entirely from the ecosystem, denying pollinators of yet another food source.
Cultivars and introduced ornamentals have their own places in our gardens. They provide us with color, texture, structure and fragrance that create sanctuaries we need as a buffer from the hectic world surrounding us. Pollinators too need some sanctuary space. Because of habitat fragmentation and loss, environmental contaminants, diseases and climate change, the world is losing pollinators at an ever increasing rate. Their loss will have devastating effects on humans. As the USDA says, “Without pollinators, we don’t eat—it’s simple as that.” Knowing that truth, we have a responsibility to protect and nurture these essential insects whenever we can.
As you plan and plant a brand new garden, or put in a few additions to your existing beds, take time to consider how your choices will help – or harm – your pollinator partners. The more of those straight species natives (or nativars that are proven to be beneficial) you sneak in, the more you will be rewarded with a garden that is vibrant, alive and filled with captivating insect activity. I guarantee it!
