April is National Native Plant Month – Plant Choice Matters!

During Native Plant Month in April, folks in Virginia and across the nation can celebrate by planting native trees, shrubs, perennials, vines and grasses to establish habitats that allow our birds, pollinators, and all wildlife to thrive. Incorporating native plants into our basic garden designs is imperative to reverse declining populations of our birds and insects and to restore balance to our ecosystems.

Native plants are indigenous to our region and have co-evolved here over centuries with our local insects, birds and other animals. Together, they make the Virginia Piedmont unique, providing wildlife with food, cover, and places to raise their young—thus supporting biodiversity and forming the basis of the food web and healthy ecosystems.

According to research published in 2019 by the journal Science, the total breeding bird population in the U.S. and Canada has dropped nearly 30 percent since 1970. Flying insects like moths have declined more than 75 percent since the 1990s. Insects pollinate 90 percent of our flowering plants, and without these insects and other pollinators, we will lose these plants and the food web collapses.

Because native plants are fully adapted to our local climate and soils, they can thrive in situations where exotic garden plants struggle. Once native plants are established, there should be less need for extra water, chemical applications of fertilizers, or any pesticides, thus protecting our waterways by reducing pollutants and nutrient runoff. Every ecoregion has different native plant communities. Charlottesville and Albemarle County are in the Northern Piedmont Native Plant ecoregion.

Studies have shown that the particular native plant selections gardeners make can have a tremendous impact on the diversity of plant life in our landscapes. Years of observations and research by University of Delaware entomologist Dr. Douglas Tallamy and his assistants have revealed that certain species of native plants, which he terms “keystone plants,”play a major role in supporting a healthy food web. Keystone plants are native plants critical to the food web and necessary for many wildlife species to complete their life cycle.

There are two types of keystone plants, according to the National Wildlife Federation:

  1. Host plants that feed the young caterpillars (Lepidoptera) of approximately 90% of butterflies, moths, and skippers. Their foliage serves as nourishment for the protein-rich caterpillars, which in turn are important components in the diets of many animals, including the young of most birds.
  2. Plants that feed specialist bees that only eat pollen from specific plants. Keystone plants for native bees feed both specialist and generalist bees.

It turns out that not just any native plant will do. Plant choice matters! Tallamy’s research finds that 90 percent of what caterpillars eat is created by only 14 percent of native plant species, with only five percent of the powerhouse plants taking credit for 75 percent of food. “Take a keystone native plant like an oak tree. More than 500 caterpillars can eat that oak tree,” Tallamy explains. “That allows for a more complex and more stable food web. These keystone or ‘powerhouse’ plants that support the caterpillars are doing the majority of the work, and without them the food web is doomed.”

In the mid-Atlantic region, we have more than 2,000 native plant genera, of which Tallamy’s team has categorized 38 as keystone plants. Native oaks, willows, birches, and wild cherry trees are in the trees list. The most powerful herbaceous plants include goldenrod, asters, and perennial sunflowers. For a summary, see Keystone Plants Native to Piedmont Virginia on our website. https://piedmontmastergardeners.org/wp-content/uploads/2023/04/keystone-native-plant-species-20-2.pdf

Tallamy makes a compelling case for homeowners to include keystone plant species native to our region in our landscapes. By supporting local insect populations, these plants create more productive landscapes that help restore ecosystems and support the food web. Select a diversity of native keystone plants to have the most impact, and pick plants suited to your existing soil, moisture, sunlight, and other site conditions.

Again, plant choice matters. Rather than select a plant that is just pleasing to the human eye, choose plants that also support the complex web of life. Healthy ecosystems provide the basic services upon which we all depend. By bringing keystone plants into our yards, we can do our part to support healthy ecosystems and the benefits they provide to humans and wildlife alike.

Learn more about native plants in our area by visiting our website, and check out Tallamy’s YouTube presentation on Native Keystone Plants for Wildlife.

https://webapps.albemarle.org/nativePlants/default.aspx

OR

  • Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, Timber Press, 2009.
  • Tallamy, Douglas W. “Keystone Plants.” Notes, Pennsylvania Native Plant Society, Spring 2019.
  • Tallamy, Douglas W. The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees, Timber Press, 2021.