Invasive and Noxious Plant Problems

Water Conservation for Lawn and Landscape June 11, 2015 Print Friendly and PDF

Purple Loostrife (Lythrum salicaria) is considered a noxious weed that invades wetland areas. It is considered invasive in all lower 48 US states. Photo credit: Ron Schott Flickr CC BY-NC-SA 2.0


Burning bush also called Winged euonymus (Euonymus alatus), is considered an invasive shrub in some parts of the US. Photo credit: Susan Buffler


Norway maple (Acer platinoides) an invasive, yet widely popular, street and lawn tree readily reseeds itself. Photo credit: geneva_wirth Flickr CC BY-NC 2.0


English Ivy (Hedera helix), a noxious weed, takes over a tree in Virginia. Photo credit: Miles Grant Flickr CC BY-NC-ND 2.0

An invasive plant is " an alien species (non-native) whose introduction does or is likely to cause economic or environmental harm or harm to human health.” 

Highly invasive plants that are threats particularly to agricultural production and clog waterways are considered 'noxious'.  These plants are highly regulated and are illegal to buy, sell, or grow.

Why are invasive and noxious plants bad?

According to the United States Environmental Protection Agency (EPA) invasive and noxious weeds are bad for the following reasons:

  • Spread out of control and overwhelm native vegetation reducing biodiversity
  • Mixing with native plants alters their genetic makeup
  • Harbor pests harmful to other plants
  • Produce toxins lethal to certain animals
  • Change soil chemistry and fire regimes
  • Change hydrologic regimes (how water flows in the landscape)
  • Cause billions of dollars of damage every year, and millions of dollars are spent on eradication

Invasive plants were brought to the United States for ornamental reasons, as forage for livestock, and for soil stabilization. Many of these plants arrived accidentally on ships or other means of transport and are spread by people, birds, and other animals accidentally carrying seeds on clothing and fur.

Some Landscape Plants Considered Invasive

We tend to think of invasive plants as undesirable weeds, however, many popular landscape plants are considered invasive.

Some states have made certain landscape plants illegal to sell. For instance, the state of New Hampshire has banned the sale of burning bush, Norway maple, and Japanese barberry. 

Some plants may be considered more invasive in some parts of the country than others. For instance, water hyacinth does not survive freezing winters but is invasive in the southern US. Some invasive plants can be controlled with time and effort. 


The National Arboretum recommends following these steps to reduce the amount of non-native invasive species in the landscape:

  • Contact your local native plant society or state Department of Natural Resources to find out which plants are invasive in your area
  • Lots of information is available on the Internet
  • Learn to identify locally important invasive plants
  • Remove invasive plants on your property or prevent their spread
  • Only use non-invasive plants when landscaping your property
  • If your property borders a natural area, consider using only native plants in your landscape
  • Find non-invasive or native alternatives for invasive landscape plants
  • Use systemic herbicides carefully as a last resort to remove invasive plants
  • Make others in your neighborhood aware of invasive plants


General Information:

Center for Invasive Plant Management

The United States National Arboretum

National Invasive Species Information Center: United States Department of Agriculture National Agricultural Library

National Resource Conservation Service (NRCS)

Additional Resources by Region:


Washington: The Myth of Well-Behaved Ornamentals


Vermont - Invasive Plants Considered for Quarantine Rule


Indiana: Noxious and Invasive Weeds and The Weed Laws of Indiana


Alabama: Ornamental Alternatives to Exotic Invasive Species



Connect with us

  • Facebook
  • YouTube


This is where you can find research-based information from America's land-grant universities enabled by



This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.