What is a Native Plant?

Having been a naturalist long before a gardener, my preference has always been to use native plants in the garden where possible. Granted, there are many non-native plants that can find a useful place in a well-designed garden, but the native options readily contribute to a natural landscape, while providing food and habitat to birds and other wildlife.

Native plants can be better choices for many landscaping applications, because they:

• Are adapted to local climate, soil, and hydrologic conditions
• Possess natural defenses to pests and diseases
• Provide food and habitat to wildlife
• Support a healthy pollinator population
• Tend to be less invasive
• Tend to require less maintenance, irrigation, fertilizers, pesticides
• Safeguard biodiversity and a balanced ecosystem.

Interest in creating natural, pollinator, and habitat gardens, as well as installing various green infrastructure technologies (e.g., bioretention basins, rain gardens, and planted riparian buffers) for improved stormwater management is driving much of the current demand for using native plants. This leads to some frequent questions:

• What exactly is a native plant?
• Which plants are native?
• Where does one obtain plants that qualify as being native?
• Does it matter if a plant is purely native?

Simply put, native plants are indigenous — that is, they occur naturally in the region in which they evolved.  They have adapted to the local ecosystem over a long period of time and in conjunction with other living organisms, which means they are an integral part of the ecosystem.  But, from there it gets complicated.  What is local? What is the region?

There are many lists available identifying those plants that are native by state or by county. Check with your local native plant society or extension service. One thorough source of native plant information searchable by state is the USDA Plants Database.

But a list by state, county or region can only be partially accurate, because ecosystems do not evolve within political boundaries.  So, unless you are sourcing your plants from the immediate vicinity, they will probably not be perfect natives.  And trying to transplant native plants from the wild has limits, including lower survival rates and, of course, obtaining permission from property owners.

So how close does your plant nursery or garden center need to be to ensure your purchased plants will function well within your native ecosystem garden?  Sometimes it is suggested to limit your sources to no farther away than 50 miles, or 100 miles.  Again, this is completely arbitrary and no different than suggesting you only buy plants cultivated within your own county or state. 

An alternative approach to defining native plant regions is to rely on ecoregions, one version of which has been catalogued by the US Environmental Protection Agency specifically to map ecosystems (biomes) with similar characteristics.  While theoretically compelling, the use of ecoregions to define native plants can also be flawed — the most narrowly defined regions (Level IV) may still be too small to make good geographic purchasing decisions.  And the larger-sized regions (Level III) generally cross significant ranges of territory, and sometimes multiple USDA hardiness zones, so plants obtained within the same ecoregion may not even be winter hardy in another part of the same region.

Garden centers typically stock their plants from a variety of their own wholesale sources, some of which may not be grown locally.  So, even if your local plant store specializes in native plants, their source will determine how well adapted the native stock will be to local conditions. 

Another complicating factor is that many native plants have been bred to modify their various characteristics, including hardiness, appearance, and disease resistance.  In many cases, the resulting cultivars become more marketable garden stock, while losing some of their native characteristics, including original appearance, form and even their natural role in a diverse ecosystem.

The picture at the top of this post shows a cutleaf coneflower (Rudbeckia lanciniata var. hortensia).  While this long-time, double-flowered cultivar is often described as a native plant, there is very little resemblance to the original native, single-flowered form.

There are many reasons to include native plants in your garden, but the distinction of what is and isn’t a native plant is rarely clear-cut.  These blurred lines have been further complicated by breeding of cultivars and by wholesale shipment of plant stock over long distances.  So, while it is beneficial and encouraged to use many native plants in your gardening projects, please don’t be disappointed when you experience first-hand that it is nearly impossible to find purely native plants.