By Deborah Pilkington, EMGV
There’s been a lot of discussion recently about native plants, non-native plants, cultivars, and nativars. But what does it all mean?
There are two really important pieces to the definition of native plants:
First is location of origin: A native plant is a plant that occurs naturally within a given area or eco-region. Thinking from large to small, we can we can talk about plants native to North America, native to the continental United States, native to the Eastern Temperate Forests, native to the Southeast, native to North Carolina, and native to the Piedmont area of North Carolina.
Second is the co-evolution over immense periods of time of that plant with native insects, bees, butterflies, and birds. Why is this important? Because native wildlife and native plants have a mutually beneficial relationship. For wildlife, the plant provides food in the form of nectar, pollen, leaves, fruits and seeds. It also provides housing in the form of hollow stems where insect larvae can overwinter, stems where caterpillar chrysalises can attach until a beautiful butterfly emerges, and cover and nesting places for birds. In return, the wildlife ensures the reproduction and continuation of the plant species through pollination and the spreading of seed. This relationship has evolved over many eras of time in a given eco-region.
A Nativar is a native plant that has been altered in some way by humans to produce a desired result. Nativar is a term that denotes when a native plant is cultivated, i.e., selectively bred by human intervention. Native plus cultivar = Nativar. What would a human want to change about a native plant, and why? The why part first: To sell more plants. The what? Here are some of the things that can be changed through cultivation of a plant:
- Flower anatomy (size of openings for insect access)
- Flower size
- Flower color
- Number of flowers on a stalk (e.g., double blooms)
- Length of bloom time
- Plant habit (upright, spreading)
- Leaf color and variegation
- Resistance to disease
- Ability to produce seed
- Increased fruit production
- Increased fruit size
So, what’s wrong with a beautifully colored, disease-resistant, double blooming, purple-leaved plant? Nothing. Except—remember the native wildlife? Research has given us some interesting data on whether native wildlife can continue to be in a mutually beneficial relationship with these “new and improved” plants.
First of all, altering the anatomy of a flower can impair the ability of insects to properly identify flowers, and access the pollen and nectar that those flowers may produce.
Secondly, native insects are often not able to eat foliage that has been bred to be purple, because it contains a chemical called ‘anthocyanin,’ and the insects do not have the ability to digest this chemical.
Thirdly, many of these nativars are sterile—that is, they don’t produce seed, so they don’t feed seed-eaters like finches, and they are short-lived. They can only be reproduced by (human) cloning, so once the plant dies, you must buy a new one to replace it. Because these plants are reproduced by cloning, they are genetically identical. Genetic variety across even plants of the same species allows the species as a whole to be better able to handle new or harsh conditions. Large clonal plantings of nativars can easily be taken out when a new disease or pest moves in, or as environmental conditions shift as they are expected to due to climate change.
And finally, increased fruit size and fruit production has not been shown to benefit fruit-eating wild creatures.
On the plus side for nativars, a longer bloom time means more food over a longer period of time. Increased disease resistance means plants that don’t succumb to common diseases. It also means less need of “cides”, e.g., pesticides in the garden. And in the case of a more upright plant, if the stems are left up over winter, it leaves more potential room for overwintering insect larvae.
Much more research needs to be done on whether the nectar and pollen that nativars produce are equal in food benefit to wildlife as the native species.
A non-native plant (also called exotic, alien, or introduced) is a plant whose origins are outside an eco-region. Over many years, non-native plants have been imported from all over the world to grace and enhance American gardens. A non-native plant brings challenges with it for our wildlife: There has been no period of co-evolution, so our native wildlife may be unable to use the plant for food–case in point, a beautiful plant with perfect leaves (leaves that haven’t been munched on, sucked from, or generally disturbed in any way). Or it may produce fruit that is not only unhealthy for birds, but may also poison them instead.
Secondly, non-native plants may muscle away resources from native plants: sunlight, water, soil nutrients, and space. In some cases, non-native plants may so ferociously outcompete native plants for these resources that the native plants die. These non-native plants are then often referred to as invasive. Avoid these plants altogether.
* Resources and Further Reading
- Tallamy, Douglas W., Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, 2007, Timber Press
- Darke, Rick and Doug Tallamy, The Living Landscape: Designing for Beauty and Biodiversity in the Home Garden, 2014, Timber Press
- Mellichamp, Larry and Will Stuart, Native Plants of the Southeast: A Comprehensive Guide to the Best 460 Species for the Garden, 2014, Timber Press
- Tallamy, Douglas W., Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard, 2019, Timber Press
- Choosenatives.org promotes North American native plants in order to nurture healthy, balanced ecosystems and help restore natural habitats for all wildlife populations. Provides information on planting natives, advocating for critters, developing pesticide-free landscapes, identifying invasive aliens, and assisting Mid-Atlantic region gardeners in locating native plant nurseries and plant sales.
- What’s in a Nativar (Carol Becker, Landscape Architecture Magazine) discusses the influence the native plant community had on the horticulture industry, research on nativars supporting insect and bird life, and the Migratory Bird Garden at Chicago’s Shedd Aquarium, including plant list.
- Are Nativars OK? (Keith Nevison, Fine Gardening Magazine) a study of phlox nativars and a discussion on how cultivars might affect pollinators.
- Mt Cuba Center a botanical garden in Delaware, whose expert researchers seek to expand the knowledge and appreciation of native plants and promote conservation.
- Landscaping for Wildlife with Native Plants (NC State Extension) describes the problems associated with some non-native, invasive plants and presents a detailed list of native plants that may be used in place of these foreign ornamentals to attract wildlife to your property.
- Wildlife Friendly Landscapes (NC State Extension) discusses landscaping for wildlife in urban settings, discusses native plants that can be used as an alternative to invasive exotics, points to resources for purchasing native plants, and includes a step-by-step guide for including native plants in your landscape.
Online Native Plant Lists
- Top 25 Native Pollinator Plants for North Carolina (Debbie Roos, North Carolina Cooperative Extension, Chatham County Center)
This post originally appeared as educational content for the Backyard Treasures Plant Sale.