Invasive Exotics

Everyone knows that kudzu has taken over parts of the landscape that edge our highways. Given the right conditions, kudzu can completely cover a tree in a matter of days, and no gardener would knowingly transplant it in his or her yard.  Fact is, this plant was intentionally introduced into the United States to reduce soil erosion and got completely out of control.  Similarly, no one would choose to plant crabgrass within a lawn, but the US Patent Office introduced it thinking it would make a good forage plant.  Imagine your lawn without crabgrass.

These are just two familiar examples of invasive exotic plants and the havoc they can produce.  But many gardeners are buying other plants at home garden centers and nurseries with the potential to do as much damage to the vegetation and wildlife of North Carolina as kudzu and crabgrass.

An exotic plant is one that is not native to an area, in our case North Carolina.  It is invasive if it is capable of rapid reproduction and is lacking in natural predators and diseases to control it.  Most of the exotic plants in North Carolina come from areas of Asia and Western Europe that have a similar climate and other environmental conditions as ours.  We are drawn to them for use in our gardens for their colorful berries or their pest resistance or ability to tolerate harsh conditions, and it is for reasons such as these that the potential for invasiveness is greatly increased.

Rest assured that not all non-native plants are invasive.  Many garden exotics, such as roses and pansies, are not a concern and only a small percentage of exotics are known to be a problem.  Yet many gardeners are planting species that can escape the environment of a flower garden and become a nuisance in their own yard or possibly a real threat to the flora and fauna of our area, decreasing space for native plants that more adequately use the resources of light, water, and nutrients and provide better food and protection local animals and birds.

Some commonly used landscape plants that are known to aggressively displace native vegetation are English ivy, mimosa, Chinese privet, Japanese honeysuckle, and beach vitex.  Invasive exotics that presently pose a lesser threat but have not become a full-scale problem are nandina, Queen Anne’s lace, and Oregon grape.  These are just a few examples.

As part of good gardening practice, plant lovers should familiarize themselves with exotics that have the potential to be destructive so an informed decision can be made.  Particular plants already in the yard could be removed, some you may choose not to add to a garden in the future, or some, like English ivy, could be used and controlled by planting them in a pot.

Several organizations in North Carolina have compiled lists of risky exotics that you can refer to when planning your garden.  The North Carolina Native Plant Society publishes a list, available on the internet, based on three levels of potential for invasiveness (http://www.ncwildflower.org).  Other lists can be found in the North Carolina Extension Service’s publication Landscaping  for Wildlife with Native Plants and at the North Carolina Botanical Garden website (http://www.unc.edu/depts/ncbg).

All three resources also list plants that are native to North Carolina that can be used as replacements for the invasive exotics in your landscape.  Many of the natives will be just as beautiful, will need less care, and possibly serve as an attraction to local populations of butterflies, humming birds and other welcome wildlife to your yard.  So why not choose a native plant instead?

 Published in the Sanford Herald.