What is a Native Plant?

monarch caterpillar on a native milkweed plant
A Monarch Caterpillar feeds on Common Milkweed in Pennsylvania. This is the only plant that supports the caterpillar on their way to becoming a butterfly. The two species, both native to North America, have evolved side-by-side over millennia.

It’s not always easy to define a native plant. You cannot say a plant is native to a particular U.S. state, as that’s too limited a description. Plants are native to regions or continents: North America, Central America, The Appalachian region of the U.S., Midwest U.S., Central Europe, China, North Africa, Japan, etc.

The EPA’s definition of native plants

In the U.S., the official definition of a native plant is : “Native plants (also called indigenous plants) are plants that have evolved over thousands of years in a particular region. They have adapted to the geography, hydrology, and climate of that region. Native plants occur in communities, that is, they have evolved together with other plants. As a result, a community of native plants provides habitat for a variety of native wildlife species such as songbirds and butterflies.

The EPA’s definition of native plants makes no mention of humans. So we might add that native plants are those that have evolved and adapted over a particular geographic range (for instance, North America, from Canada to Florida), without human intervention.

Local adaptation of plants

Even within their natural geographic range, native plant species are genetically adapted to local growing conditions. This adaptation is typically referred to as “local provenance” or “ecotype”. An ecotype is a subset of a species that possesses genetic adaptation to local growing conditions. Sometimes ecotypic adaptations are visible to us as variations in shape, size, or color. Other ecotypic adaptations are not readily apparent, for example adaptations to various soil chemistries, minimum winter temperatures, and drought tolerance.

University of Maryland Extension Service

Not as simple as you thought? Join the club. A Red Maple native to Florida may not survive in Canada, even though it’s native to both. Local adaptation is very important.

The good news is, many garden centers and plant nurseries specialize in native plants, so if the nursery is reputable, you can be confident you’re choosing a plant well-adapted to your climate. All bets are off at big box stores.

viburnum flower
There are about 175 species of Viburnum shrubs, native throughout the Northerm Hemisphere. Most produce beautiful flowers in spring and berries for wildlife in fall and winter.

Why use native plants?

The benefit of using native plants is in creating a sustainable, low maintenance habitat. A shrub, tree or flower native to your local area has co-evolved with other shrubs, trees, flowers, and wildlife to create and support a diverse and robust ecosystem. Specific birds eat specific caterpillars in specific trees, native bees prefer the nectar of certain local native flowers, and your local native pine species have been a winter wildlife habitat for eons.

  • Native plants provide a hardy, drought resistant, low maintenance landscape that benefits your local ecosystem. Native plants eliminate or reduce the need for fertilizers, pesticides, water, and lawn maintenance equipment. This saves you time and money.
  • Native plants rarely need synthetic fertilizers. Excess phosphorus and nitrogen (the main components of fertilizers) runs off into lakes and rivers. This runoff causes excess algae growth in waterways which depletes oxygen, harms aquatic life, and interferes with recreational uses. Only a soil test can determine if your garden needs fertilizer.
  • Native plants provide shelter and food for wildlife. These plants attract a variety of birds, butterflies, and other wildlife by providing diverse habitats and food sources. Local wildlife has evolved side by side with these plants over millennia, creating a symbiotic relationship.
  • Native plants require fewer pesticides. Pesticide runoff contaminates local rivers and lakes.
  • Native plants promote biodiversity and stewardship of our natural heritage. Natural landscaping is an opportunity to reestablish diverse native plants, and that invites the birds and butterflies back home.
  • Native plants require less water than lawns. In urban areas, lawn irrigation uses as much as 30% of the water consumption on the East Coast and up to 60% on the West Coast. The deep root systems of many native plants increase the soil’s capacity to store water, which reduces water runoff and helps manage flooding.
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Native plants require less maintenance

Planting native also means less work for you. A plant adapted to your ecosystem has a better chance of surviving heat waves, droughts, flooding, extremely cold winters, and local pests and diseases. Previous generations of that plant have survived these challenges and more and its genes have adapted to survive local conditions.

This is also a serious consideration as climate change picks up speed. A native plant has a much better chance of surviving whatever’s coming its way than a species imported from the other side of the world.

 Buy on Amazon: The Living Landscape: Designing for Beauty and Biodiversity in the Home Garden 
native mountain laurel
Mountain Laurels are native to Eastern North America. The various species appear in the wild in many settings including sandy woods, open meadows, rocky slopes, and woodland margins. Many native Mountain Laurels can be grown in your garden.

How do non-native plants affect native plants?

When we plant non-natives, they can act quite aggressively in the landscape. They have few enemies to control their spread and as they move in, complex native plant communities, with hundreds of different plant species supporting wildlife, are crowded out by the non-native plant. This creates a monoculture in which the native community of plants and animals is reduced and simplified, with most native plant species disappearing. This leaves only the non-native plant population intact. We hear about invasive species frequently when a new insect pest appears in our local area – they overrun and at times destroy the landscape. The same thing can happen with non-native plants.

Again, from the EPA website: “For example, Purple Loosestrife colonizes wetland areas, replacing native plants unable to compete for available sunlight, water, and nutrients. Wetlands infested with purple loosestrife lose as much as 50% of their original native plant populations. This limits the variety of food and cover available to birds and may cause the birds to move or disappear from a region altogether. 

So there you have it. Go native.

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purple loosestrife
Purple Loosestrife, native to Europe and Asia, is beautiful but incredibly invasive in North America. It colonizes quickly and wipes out native plant species.

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