If you’ve spent time outdoors in North Carolina, you have likely spotted some “green invaders” whether you knew it or not. We’re not talking about aliens from outer space, but invasive plants that sneak into our state, displacing our native plants and harming ecosystems and wildlife. To protect forest ecosystems and wildlife in North Carolina, one should be mindful to plant native species and reduce the spread of invasive species.
Not all exotic plants are harmful. For a plant to be considered invasive, it must outcompete native species, reproduce and grow quickly, and typically dominates ecosystems. When an invasive plant enters a new area, its natural enemies typically don’t accompany it, so essentially, the invasive plant is free of things that keep it naturally “in check” in its native range. Invasive plants reduce biodiversity by dominating habitat that is normally used by native species. Invasive species overtake the native vegetation that birds, mammals, insects, and other animals depend on for food and shelter. In addition to outcompeting native species, invasive plants can pose a threat to humans. Some invasive plants produce chemicals that are toxic to people. For example, Chinese privet produces fruit which causes adverse symptoms if consumed, and floral odors from the plant may even cause respiratory irritation. Many invasive plants are also highly flammable, making wildfires and prescribed burns more dangerous. Clearly, it is important that North Carolinians cultivate native plants and remove invasive plants when discovered.
There are a variety of invasive trees, shrubs, vines, and grasses that have slipped into North Carolina already, many a threat to our forest ecosystems. The North Carolina Native Plant Society has an extensive list of invasive plants in our state along with a ranking of their severity. A few of these plants include cogongrass, Callery pear, and kudzu.
Cogongrass is a state and federal noxious weed which is considered one of the top 10 invasive weeds in the world. The density of the grass makes it unsuitable for wildlife to burrow or forage, and the grass outcompetes native plants for resources. It also burns very hot, making forest fires and controlled burns dangerous to ecosystems and humans managing fires. Since 2012, it has been found ten times in North Carolina and has been eradicated from three of these ten sites. The goal is to eradicate the weed from our state completely, so timely reports and a swift response is critical.
Another threat to our forests is Callery pear (of which the popular ‘Bradford pear’ is a variety), an invasive tree that is often used to landscape residential areas. Hailing from China, this deciduous tree invades disturbed natural areas and displaces native plants. It easily spreads as animals disperse its seeds.
Lastly, kudzu is another example of an intentionally introduced plant species that backfired. It was brought into the United States from Asia in the 1800s for livestock forage and erosion control. However, since then, it has spread across the South, including North Carolina. Kudzu grows quickly, covering other plants, breaking branches and shrubs, and even overtaking buildings and other structures. The pesky vine is very difficult to get rid of.
To reduce the spread of invasive plant species, there are several actions we can take. Invasive plants are more likely to take over disturbed areas, so it is important to minimize disturbances in natural communities where we can. By being aware of which species are invasive, we can also prevent planting them. Gardeners should use non-invasive alternatives, pay attention to new sprouts, and remove any invasive species. We can also prevent the spread of invasive plants by watching out for hitchhikers; clothing, vehicles, and belongings can carry seeds and plant pieces, so it is important to remove them if they are noticed. By learning to work with natural systems and keep an eye out for green invaders, we can protect our native species.