A number of troublesome weeds threaten to worsen in Vermont as the climate changes. Warmer temperatures and heightened carbon dioxide concentrations favor non-native weeds over native plants. The most troublesome plants are invasive species.
An invasive species is a non-native species that causes major environmental, economic, or public health problems. Many non-native species never reach invasive status and some native species can act like invasives. In Vermont, especially harmful invasive species are classified on a noxious plant list.
Many invasive species have been in the U.S. for decades, even centuries, and have only recently become problematic. Often, repeatedly importing a plant over a long period of time can provide a population with enough genetic diversity to succeed. Sometimes, there wasn’t an opportunity to invade new habitats until years later — for example, the increase in the number of roads has given invasive plants increased opportunities to hitch rides on tires to new habitats.
Efforts to control the spread of invasive species have met with mixed success. Some plants, like kudzu in the South, grow so quickly that removal is challenging and expensive. Cutting or applying herbicide to small populations on the frontier of an invasive plant’s advance appears to work best. Because many invasive plants are highly adaptable, they are poised to adapt to climate change more quickly than most native plants.
See a slideshow below.