This is a a classification of a plant based on where it has historically been found. Where it has been it is native, where it has not, non-native. Some design requirements or certification methods look specifically for the use of native plants. However, using only native plants can limit the availability of plants for the design as hand.

Native: A species, sub-species, or lower taxon living within its natural range (past or present), including the area in which it can reach and occupy using its own legs, wings, wind/water-borne or other dispersal systems, even if it is seldom found there.

Non-native or alien or exotic species is: “a species, subspecies, or lower taxon introduced outside of its normal past or present distribution; includes and part, gametes, seeds, eggs, or propagules of such species that might survive and reproduce.

This scientific focus on species as a reference is what will be used for defining native and non-native plants for the purpose of the study. The spread of nonnative species does not stop at a state or national border.

3 Main Issues:
native plants are often sold in a specific region, while non-native plants are more widespread. the framework will focus on plants native to the area and nonnative cultivars. The economics involved in growing natives is more expensive than and not as established as currently grown cultivars, thus not as widely available. The industry has a wide variety of definitions for native plants and the regulation that surrounds them, making it difficult to truly know what a constitutes a native plant.

3 Stages to an invasive plant:
When it is first introduced (transported by humans across a major geographical barrier), then is naturalized (overcoming abiotic and biotic barriers to survival and regular reproduction) and then the plant becomes invasive by moving to a site distant from the first induction. there are three stages of invasion: widespread but rare (IVa), localized but dominant (IVb) and widespread and dominant (V). See these for more information on Cultivar and native and non-native: (Norcini, 2007) and the Virginia Nursery & Landscape Association, Colautti, & MacIsaac, H. (2004).