This is a question I get asked a lot, and surprisingly there isn’t consensus. There are vague definitions as seen below, but the jury is still out on a strict definition of what constitutes a native plant.  The ambiguity lying in when human intervention occurred and in what space that place is native to. (i.e. a plant can be native to Canada, but not native to Ontario).  This can be taken down to ecosystems, with some native plant purists holding that a plant is only truly native if it existed in that plant community/ecosystem prior to human intervention …. but when was that again? You get my point.

Native plants are uncultivated flora indigenous to geographic regions, which have adapted over time to various environmental and social influences such as soil types and hydrology, micro-climates and human influence.
Ecological Landscape Association
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Native plants are plants indigenous to a given area in geologic time. This includes plants that have developed, occur naturally, or existed for many years in an area (trees, flowers, grasses, and other plants).
Wikipedia
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.
Wild Ones

For the sake of simplicity and non-native puritans, here is my interpretation of what a native plant is.

A native plant is one that occurs naturally in Ontario or a particular region, ecosystem, or habitat prior to European contact.

Alternative, sometimes confusing terms

Wildflower
Often used interchangeable with native plant, a wildflower does not mean it is a native plant. This can lead to some mis-representation from seed and plant growers, selling non-native species as wildflowers being marketed for the benefits of native plants.

Naturalized
A naturalized plant is also very similar to wildflower in the sense that the word holds little value when defining a specific plant.  For me, a naturalized plant is a native or non-native species that occurs naturally, without human intervention in an ecosystem. For example, a dandelion (non-native) found in a field is a naturalized plant.

 

Are native plants important?

Yes! Plants are a cornerstone of biological diversity. Native plants do the best job of providing food and shelter for native insects, birds and animals.

Learn more about why you should be including native plants in your garden.