Invasive Species

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Canada thistle (Cirsium arvense), a common invasive species on PEI.

Approximately 1,300 different types plants can be found growing on Prince Edward Island.  About one third of those plants are naturalized non-natives – plants that have arrived, or been brought here from somewhere else, and survived in nature without cultivation. (PEI Forests, Fish and Wildlife)

Not all non-native species become invasive.  Most of the plants we purchase at garden centers are not native species and most are not invasive, but some are.  Learning to identify plants in your garden and in nature can be the first step in preventing further spread of invasive species.

Invasive species, once they have been introduced to a new area, have a tendency to spread.  They are able to do this, firstly, because they lack the natural controls that keep native species populations at sustainable levels (i.e. disease, competition, predators, etc.).  Second, a common theory on why invasive plants are able to survive and thrive in new environments is that they have certain traits or combinations of certain traits that allow them to outcompete native species for resources (i.e. light, water, nutrients).


Common traits and associated advantages of invasive plants