Ask Mr. Smarty Plants

Although the term "Native Plant" has become firmly entrenched in the botanical, horticultural and, to some extent, the public vocabulary there is surprisingly little consensus on its definition despite widespread use (see definitions below).

Clearly, there is no "one size fits all" definition of native plant, although a closer inspection reveals that there are some common threads shared by most. The first common thread is the human factor. The human element is either implied in statements like “occurred, grows or evolved naturally” or stated explicitly in statements like “not introduced by man, without direct or indirect human intervention, or prior to European contact”. Native plant definitions that exclude humans or arbitrarily assign a point in time before which (but not after which) human intervention is allowed are, by default, definitions that assume humans are not part of the natural world. Nevertheless, the human exception appears to be a key and, sometimes, difficult to document, criteria when assigning native status to a plant.

The second common thread is place. Each definition defines a native plant as occupying a particular area, region, habitat or ecosystem to distinguish native from non-native. This element introduces geographic confusion to a native plant definition. To whit, a species can be native to the United States (but non-native to a specific state) or native to a state (but non-native to a particular area within that state). By this line of reasoning, all species are native to planet earth (but may be non-native to any particular place on the planet).

In my opinion the best native plant definitions are the ones that incorporate the provenance and evolutionary history of a plant group or lineage. Take, for example, the definition offered by Wasowski in The American Gardener[1] in 1998, “Native plants should be defined as those that have evolved and adapted to a specific location and have remained genetically unaltered by humans.” This definition takes into account time and place, as well as the human element. More importantly, it implies a connection between generations through a shared evolutionary ancestry.

So what is a native plant? It is actually pretty simple to summarize Wasowki to define a native plant as … a plant that occurs naturally in the place where it evolved.

Native Plant Definitions

A population of plants within a defined geographic area that exist there without direct or indirect human introduction (Andrea De-Long Amay after lunch with Joe and Damon)

One that exists in a given region through non-human introduction, directly or indirectly (Andrea De-Long Amaya, Lady Bird Johnson Wildflower Center)

A plant occurring naturally in an area and not introduced by man; indigenous (GardenWeb)

With respect to a particular ecosystem, a species that, other than as a result of an introduction, historically occurred, or currently occurs in that ecosystem (US Fish and Wildlife Service)

A Native plant is one that occurred naturally has existed for many years in an area. These plants can be trees, flowers, grasses or any other plant. (Wikipedia)

All indigenous, terrestrial, and aquatic plant species that evolved naturally in an ecosystem (US Forest Service)

A plant that lives or grows naturally in a particular region without direct or indirect human intervention (USDA and (US National Arboretum)

Any plant that occurs and grows naturally in a specific region or locality (The Garden Helper)

Native plants are those that evolved naturally in North America. More specifically, native plants In a particular area are those that were growing naturally in the area before humans introduced plants from distant places. In eastern and central North America, native plants typically grew in communities with species adapted to similar soil, moisture, and weather conditions. Some of the widespread communities included oak-hickory-chestnut and beech-maple forests, tallgrass and shortgrass prairies, and freshwater marshes. Additional communities occupied specialized niches, including savannahs, fens, bogs, flood plains and alpine areas. (Wild Ones)

A native plant species is one "that occurs naturally in a particular region, state, ecosystem, and habitat without direct or indirect human actions" (Federal Native Plant Conservation Committee, 1994) A native plant, within a specified geographical region of interest, is a plant species (or other plant taxon) currently or historically present there without direct or indirect human intervention. (Larry Morse, L.E.M. Natural Diversity) Any plant which is a member of a species which was present at a given site prior to European contact (California Native Plant Society)

[1] Wasowski, Andy. "Provenance, defining our terms.(native plants)." The American Gardener 77.6 (Nov-Dec 1998): NA.