What are non-native, invasive plants and why are they a problem?

A: Plants brought by people to a new region are called non-natives or exotics.  Invasive, non-natives are those that spread extensively through large areas, forcing out native species.  They are a major threat to natural habitat and biodiversity.  Examples of invasive, pest plants are:  fountain grass (Pennisetum setaceum), eucalyptus (Eucalyptus species), Spanish broom (Spartium junceum), California pepper tree (Schinus molle), ivy (Hedera spp.) and a plethora of annual grasses.  For a a list and more information on invasive plants click here.