Native plants have virtue. They’re good for the environment. Planting them is the right thing to do. Planting them may even save the planet. How could any gardener or landscape designer not choose native plants?
I confess to reacting with a bit of resistance when I first heard statements such as these. Attending lectures showcasing native gardens that looked wilder than nature but not as beautiful made it difficult to join the native plant movement. Plant options seemed to diminish as gardening became an ethical act. Proponents were passionate, but what was missing from most presentations and publications was data – data showing that individual gardeners using native plants makes a difference.
The data are there, have been there, in books such as Doug Tallamy’s Bringing Nature Home1, but it was a research article that finally caught my attention: “Nonnative plants reduce population growth of an insectivorous bird” in the November 6, 2018 issue of PNAS (Proceedings of the National Academy of Sciences)2. A detail-rich description of the impact of nonnative plants on the food supply of chickadees (also by Tallamy, with Desirée Narango as lead author and Peter Marra as co-author), the article addresses questions about the assumed benefits of nonnative biodiversity and draws a clear picture of the interrelationships that have evolved over time among birds, their insect food sources, and the plants that support the life cycles of insects. And the article provides a useful rule for designing a garden – keep nonnative plants to less than 30% of total biomass.
Where to start if you’re new to designing with native plants? Essential Native Trees and Shrubs for the Eastern United States3 is a good resource to consult for identifying plants that form the structure of the garden. Each profile describes how the plant is used in the landscape, its characteristics in different seasons, its form, color, texture, and culture, and plants found growing nearby in the wild or that pair well in the garden. Plant characteristics are summarized in tables that make it easy to select trees for narrow spaces, trees with attractive bark, or shrubs that provide food for birds.
A useful companion for identifying native perennials is Native Plants for Wildlife Habitat and Conservation Landscaping: Chesapeake Bay Watershed4, which summarizes growing conditions and attributes for ferns, grasses, herbaceous plants, and vines, in addition to trees and shrubs.
Pull out invasive Barberry and plant wildlife-friendly Yaupon Holly (Ilex vomitoria). Switch out the Crape Myrtle for an Eastern Redbud cultivar (Cercis canadensis). Trade four-season Nandina for three-season Witherod Viburnum (Viburnum nudum, Viburnum cassinoides) and let the show of fruit in summer and fall and the birds that follow make up for the loss of winter interest.
If preserving native plants, supporting bird-insect relationships, or bringing more butterflies and bees to the garden are not convincing arguments, consider another reason to plant native: many of the plants are flat-out gorgeous.
1. Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. Updated and expanded paperback edition, 2009. Portland, Oregon: Timber Press.
2. Dove, Tony and Ginger Woolridge. Essential Native Trees and Shrubs for the Eastern United States. 2018. Watertown, Massachusetts: Charlesbridge.
3. Narango, D. L., D. W. Tallamy, and P. P. Marra. 2018. Nonnative plants reduce population growth of an insectivorous bird. Proceedings of the National Academy of Sciences of the United States of America. 115: 11549-11554.
4. Slattery, Britt E., Kathryn Reshetiloff, and Susan M. Zwicker. 2003, 2005. Native Plants for Wildlife Habitat and Conservation Landscaping: Chesapeake Bay Watershed. U.S. Fish & Wildlife Service, Chesapeake Bay Field Office, Annapolis, MD. 82 pp. (Also see online at https://www.fws.gov/chesapeakebay/pdf/NativePlantsforWildlifeHabitatandConservationLandscaping.pdf)
If you’d like to read more . . .
Clem, C. S., and D. W. Held. 2018. Associational interactions between urban trees: are native neighbors better than non-natives? Environmental Entomology. 47: 881-889.
Narango, D. L., D. W. Tallamy, and P. P. Marra. 2017. Native plants improve breeding and foraging habitat for an insectivorous bird. Biological Conservation. 213: 42-50.
“Native Plant Finder (Beta).” National Wildlife Federation. Accessed May 27, 2019. https://www.nwf.org/NativePlantFinder/
Poythress, J. C., and J. M. Affolter. 2018. Ecological value of native plant cultivars versus wild-type native plants for promoting hemipteran diversity in suburban areas. Environmental Entomology. 47: 890-901.
Note: The original draft of this post was written on May 28, 2019.