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Invasive Alien Plant Species of Virginia

What are Invasive Alien Plant Species and Why are They a Problem?

This is an advisory list published by the Department of Conservation & Recreation (VDCR) to inform land managers of potential risks associated with certain plant species known to exhibit invasive behavior in some situations. It should be noted the list is not regulatory in nature, and thus does not prohibit the use of the listed plant species.

Alien plants also known as exotic, non-native, or nonindigenous plants, are species intentionally or accidentally introduced by human activity into a region in which they did not evolve. Many alien species are well known and economically important in agriculture and horticulture, such as wheat, soybeans, and tulips. Alien species, whether plant or animal, often do not become established outside of cultivation and, if they do, they usually have few impacts on natural communities.

Invasive alien plants, however, escape cultivation and become agricultural pests, infest lawns as weeds, displace native plant species, reduce wildlife habitat, and alter ecosystem processes. Across the country and around the world, invasive alien plants and animals have become one of the most serious threats to native species, natural communities, and ecosystem processes. They also exact a costly toll from human economies that depend on resources and services provided by healthy ecosystems. Examples include destruction of vast areas of western rangelands, clogging of important waterways, and increased costs in maintaining open powerline rights-of-way.

Of the 4,000 alien plant species introduced to the United States that have escaped cultivation, approximately 400 are serious invaders. Half this total was introduced for horticultural uses. Others arrived accidentally in seed mixes, packaging materials, ships ballast, and by other means. Invasive plants now infest more than 100 million acres. One study estimated that from 1901 to 1991, economic losses in the U.S. caused by 15 invasive plant species (not including agricultural weeds) were $603 million (Office of Technology Assessment, 1993). The Virginia Department of Conservation's Division of Natural Heritage and the Virginia Native Plant Society have identified 115 invasive alien plant species that threaten or potentially threaten natural areas, parks, and other protected lands in Virginia.

Once thought to be a problem only on farms or in lawns, invasive plants are now recognized as a threat to natural areas, parks, forests, and other sites in a more or less natural state. Land managers, weed scientists, foresters, ecologists, and other conservationists are joining together to face this challenge in ways that help conserve native species and natural communities and protect environmental quality.

Invasive alien plants typically exhibit the following characteristics:

  • Rapid growth and maturity

  • Prolific seed production

  • Highly successful seed dispersal, germination and colonization

  • Rampant vegetative spread

  • Ability to out-compete native species

  • High cost to remove or control

An invasive plant infestation is like a slow motion explosion, which, if left unchecked, may severely alter a site's natural, economic, aesthetic, and other cultural values. Management of invasive species while maintaining these values can appear to be a complicated and unending task. For this reason, planning and prioritizing are crucial. By articulating clear goals, gathering the best available information, and prioritizing actions based on the significance of an infestation's impacts and feasibility of control, land managers can identify how their time, effort, and money can most effectively be applied. Invasive species present a difficult challenge with no quick and easy solutions. Many unknowns exist regarding control methods and their efficacy, in addition to limited budgets for managing invasive plants. Sometimes, the best course of action may be to do nothing.

How You Can Help

  1. Use native plant species grown from local stock for conservation and landscaping purposes whenever possible. See our list of native plants for conservation, restoration, and landscaping.
  2. When using alien plants, avoid highly invasive species. See our invasive alien plants list.
  3. Support public policies that restrict the introduction of invasive alien plants and get involved in organizations that work to protect biodiversity.