What is a Native Plant?

The question arises often as gardeners seek to make their plantings more ecologically valuable. Perhaps the most accurate, if not the most helpful, answer is, “it depends.”  The Plant Northern Piedmont Natives marketing campaign may have a unique answer.

If we assume that no humans brought plants here earlier, then only those plants that greeted the first Europeans to arrive—plants with origins in deep time—should be considered truly native to our part of North America. However, defining only those plants as “native” would rule out many that today have real ecological value.

Doug Tallamy* and Rick Darke in their book, The Living Landscape, offered a more practical definition:

“a plant or animal that has evolved in a given place over a period of time sufficient to develop complex and essential relationships with the physical environment and other organisms in a given ecological community.”

Tallamy’s later books, Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, and Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard, led to the grassroots movement, Homegrown National Park. The aim of this movement is to encourage the creation of linked habitat corridors to regenerate biodiversity across the nation. Along with other pro-biodiversity efforts, it has succeeded in creating unprecedented demand for native plants. It has also brought about a great deal of frustration on the part of property owners and gardeners because straight species of local genotype native plants—those most likely to flourish and support the local food web—are not readily available to the average gardener.

Only a small percentage of plants carried by nurseries and garden centers could be considered native in any way, and the great majority of those are cultivars and hybrids rather than unchanged descendants of wild plants.**. We do have several local smaller nurseries that specialize in growing natives from seed (including Hummingbird Hill Native Plant Nursery, Little Bluestem Nursery, and the greenhouse of Wintergreen Nature Foundation). While these growers may find it challenging to compete with large producers (that can provide consistently beautiful plants in quantity), consumers seeking native options will have an easier time finding them, and a greater selection, at a smaller, specialty nursery. For a complete list of native plant suppliers, check out the Virginia Native Plant Society’s website: www.vnps.org.

As an entomologist, Tallamy offers the insects’ view of plants. That perspective has informed studies of the value of some cultivars, such as those Mt. Cuba Center has conducted. For example, one Mt. Cuba study of hydrangea cultivators included the Virginia native Hydrangea aborescens. Noting that such lacecap hydrangeas attract many more pollinators than mopheads, the study gave top marks to Hydrangea arborescens ‘Haas’ Halo’, a selection that “offers the perfect combination of horticultural excellence and pollinator value.”

Studies of plants’ attractiveness to pollinators don’t wholly define their ecological value. Like us humans, insects and animals can be attracted to foods that aren’t beneficial to their health. In the case of birds, for example, sugary berries may be consumed at a time when they need fat in their diets instead. For this reason among others, local plant genotypes are most likely to provide the right ecological services—if they are available. And apart from commercial availability, there is also the problem of natural availability: Try to find a small-scale (4 feet tall or less) evergreen shrub species native to central Virginia.

All of these issues and factors came to bear when Piedmont Master Gardeners decided to join the Plant Virginia Natives Marketing Partnership. This statewide campaign is intended to bring gardeners/landscapers and commercial suppliers together in the common cause of more native plants—and fewer exotic ornamental plants of little or no value to local ecosystems. Thus, an important aspect of our Plant Northern Piedmont Natives (“PNPN”) campaign is to inform both buyers and sellers of which plants have value for this region. Taking inspiration from a list generously shared by a northern Virginia campaign, we sought to create the most useful list possible.

Our primary resource is the Digital Atlas of the Virginia Flora, which contains the most comprehensive information available on the geographic distribution of vascular plants in the Commonwealth. We have also referred to Albemarle County’s Piedmont Native Plant Database. The great majority of species those sources identify as native are not commercially available. This may be simply because many native plants are unfamiliar and underappreciated. It is certainly also because buyers want plants that fit into designed situations, have eye-catching beauty, and resist diseases common to landscapes and gardens. Cultivars are continually being developed to meet such needs.

We sought the opinion of Repp Glaettli, author of Piedmont Native Plants: A Guide for Landscapes and Gardens.*** Taking heart from his view that the PNPN marketing campaign should “not let the perfect be the enemy of the good,” we have adopted a definition of “native” to include selections or cultivars with locally native antecedents, which are likely to be commercially available to gardeners, and which either might have occurred naturally or which have demonstrated ecological value approximately equal to the local species. Repp cautioned that the origins of many cultivars are “a black box.” So, we refer to multiple web sources—including plant patents—in the attempt to learn cultivar origins. We know that much depends on the reason for the cultivar. If it was bred to offer a new color, double blooms, a different flower shape, or red or variegated foliage, insects may not recognize it. However, if the cultivated trait is disease resistance, a larger flower, or a shorter habit, it’s likely to be fine.**** We make our best guess. (It’s a can of worms and an ongoing effort.)

The resulting list of native plants and cultivars, though perhaps not perfect, is provided to participating nurseries and garden centers, where Extension Master Gardener volunteers label those plants found on the list with bright red “Virginia Native” stickers (which we are told greatly enhance sales). The list may also be found on the Piedmont Master Gardeners website. It is frequently updated as we learn more and as our volunteers find cultivars to research.

So, what is a native plant? For your garden, it may be a cultivar with local genes.

*Doug Tallamy is the T. A. Baker Professor of Agriculture in the Department of Entomology and Wildlife Ecology at the University of Delaware, where he has authored 106 research publications and has taught insect-related courses for 41 years.

** https://www.ecolandscaping.org/11/designing-ecological-landscapes/native-plants/supply-and-demand-of-native-species/

*** Available in print from some participating garden centers and nurseries; for information on how to order the book or download it, see https://www.plantvirginianatives.org/native-plants-for-northern-piedmont

****Picking Plants for Pollinators: The Cultivar Conundrum, https://xerces.org/blog/cultivar-conundrum

SOURCES:

Featured Photo: Tiger Swallowtail on Phlox paniculata ‘Jeana’ by Bernice Thieblot

https://homegrownnationalpark.org.
http://www.hummingbirdhillnatives.com
https://www.littlebluestem.net
The Nature Foundation at Wintergreen/greenhouse
https://www.plantvirginianatives.org
https://www.plantvirginianatives.org/plant-northern-piedmont-natives
https://vaplantatlas.org
http://webapps.albemarle.org/nativePlants/default.aspx
Piedmont Native Plants/pdf
Piedmont Master Gardeners.org/Plants Native to our Northern Piedmont