Our library system periodically hosts adult Ed programs for the community. The other night there was one about turning your turf lawn into a - and I quote the presenter here - a native paradise for pollinators. Figuring he knew more than I did (ours is three years old and far from a paradise), I settled in to learn.
Although this is an extremely rural area, it is also home to a major university and lots of precise and probing minds. You could immediately tell that the presenter felt he was well prepared for his audience and eager to share his knowledge and experience. Unfortunately the poor man met his match in the first few minutes when an audience member asked an interesting question. In essence, he was asked how truly native a plant must be to be considered a native?
At first I thought he was just trying to be superior and “catch “ the presenter, but the more he spoke and the more I thought about it, I realized it was both an honest and excellent question that needed to be considered. What is a native plant? Is everything sold as “native” truly a native plant supporting biodiversity? How much does location impact native-ness? “Can a plant grown in California,” he asked, “be considered a native here in Missouri?”
Over the last few years, The phrase native plant has become a buzzword for those in or even interested in horticulture and environmental issues. Consumers are more and more seeking out native plants for their landscaping. As professionals, we may espouse the general philosophy of needing to incorporate natives in our designs, but do we actually agree on what a native plant truly is?
A standard, textbook definition of a native plant from the early 1990s is “a plant that grew wild in a particular or defined area prior to settlement by Europeans.” Grow Native!”, a nationally recognized organization whose goal is to protect and restore biodiversity, uses a somewhat broader definition. They state, “Native plants originally occur within a region as the result of natural processes rather than human intervention.”
Although both definitions emphasize the importance of location when defining a native plant – they originate in a specific area or region – the older definition ties natives to a time frame, or what was there prior to settlement by Europeans. That definition sets fairly specific limits on what can be considered a native plant. Grow Native!, on the other hand, takes a somewhat broader path, acknowledging the fact that natural processes (thinking of birds dropping seeds as they migrate) rather than human intervention can and do alter the native landscape. With this definition, the list of native species can become fluid, changing as the environment changes.
The gentleman's questions finally led to the use of cultivars in our quests to rebuild native habitats. Are cultivars, or on some plant tags Nativars, really native plants? For example, is planting a Yellow Sandy Sombrero coneflower instead of Echinacea purpurea a viable substitution, as the big box stores would have you believe?
For the vast majority of experts, the answer is a resounding NO! Cultivars/nativars are native plants that have been genetically altered by human intervention for a specific purpose. They are by definition not native. They are bred, for example, to have a more intense, or even a different color than the original species. Or perhaps the breeder feels that in order to be attractive in the landscape, the plant should be taller, or shorter, or the leaf should be showier. Unfortunately, as these genetic changes are made, characteristics that made the plant attractive to wildlife are lost. Once those traits disappear, local wildlife, especially pollinators whose numbers are already dwindling, have lost another fragment of their habitat.
There are also other long-term problems with cultivars of which most consumers are unaware. Many cultivars are cloned, meaning that they are genetically identical to one another. Without diversity in its genetics, or the ability to adapt to changing conditions, a species can easily die out, leaving a hole in the ecological web of life.
Consumers who purchase nativars have no idea where the original plants were bred. How similar are the climates? The soil types? The moisture levels? Will the cultivar survive in its new environment? Does its genetic profile meet the needs of local insects? Recent research suggests that reproduction rates of native insects decline in non-native habitats, opening the door to hoards of harmful invasive insects.
Finally, planting cultivars near patches of its original native species isn't recommended. Over time, it is likely that the cultivar and the native will interbreed. Researchers are finding that such cross-breeding can significantly weaken or even change the native’s gene pool, making both native and cultivar useless to insects and birds.
What started out for me as an interesting “how to” evening quickly evolved into an opportunity to rethink my own understanding of the relationship between native plants and native pollinators. As I listened, I realized that there was a reason that my own patch of prairie was not the pollinator paradise I thought it would be; it had been designed around people preferences rather than insect needs. It looks like I have some major landscaping renovations in my future. I'm just glad that I realize what my insect tenants need.
