Native Plant Trust

Controlling Invasives

Invasive Species Are on the Move

Help check their destructive spread where you live

Like their counterparts in the animal kingdom—Asian long-horned beetles, zebra mussels, gypsy — plants such as Japanese knotweed, Asian bittersweet, bishop's weed (pictured above), and Tatarian honeysuckle are non-native species that have spread into native or minimally managed plant systems. There they cause economic or environmental harm by developing self-sustaining populations and becoming dominant and/or disruptive to the established systems.* 

Classifying a species as invasive is not simply xenophobia projected onto the landscape. In New England, non-native plant species make up more than a third of our flora, and 10 percent of these qualify as invasive. Even species native to the U.S. may be invasive in some parts of the country and not in others. 

Invasive plants earn their label by growing and reproducing faster than native species in the same growing conditions. Free from the predators, diseases, and other plants that keep them in check in their native ranges, they monopolize the light, water, and other nutrients all plants need. Sometimes these dense colonies even alter the air temperature and soil chemistry around them, further squeezing out other plants and the animals that depend on them. 

*This definition was formulated by the Massachusetts Invasive Plant Advisory Group, of which Native Plant Trust is a founding member.

What We're Doing

Native Plant Trust works with towns, government agencies, universities, and other organizations throughout New England to assess how invasive plants are affecting the landscape and to control their spread.

In addition to researching how invasive species are affecting the landscape, we train volunteers to monitor them, compile data, and create tools to track and identify these plants:

  • We provided core data for the comprehensive Invasive Plant Atlas of New England (IPANE) website that helps professional and citizen scientists track the distribution and spread of more than 100 invasive or potentially invasive plant species in the region. We recruited, trained, and coordinated 450 volunteers to gather this information in the field.
  • For the region’s first assessment of New England’s native plants, we mined years of original research by botanists here and at member agencies of the New England Plant Conservation Program, which monitors rare and endangered species and fuced Flora Conservanda: New England, the list of plants most in need of conservation in the region. 
  • The resulting report, State of New England’s Native Plants, ranks invasive plants among the top three threats to rare plants. The report also analyzes how invasive plants are affecting all the key habitats in our region and recommends steps for controlling them. 
  • Our Conservation and Research Plans for 117 rare plant species in the region have guided the recovery of several rare plant populations from stresses that include invasive species.

What You Can Do

Check out our toolkit to see how you can prevent, detect, and control these invasive plants. 

Identify and Prevent

1. Learn to identify New England’s common invasive plants:

2. Naturally biodiverse areas have shown more robust resistance to invasive species. Here are a few ways to maintain and support thriving natural areas near you:

  • Advocate to protect places of natural diversity in your community
  • Volunteer for your local conservation commission
  • Support organizations working to combat the spread of invasive species
  • Plant New England native species in your yard and garden

3. Keep more invasive species from entering the region. Many states prohibit selling or importing certain plants. Find your state’s list of invasive and/or prohibited plants in the green box below, or click here.

4. Invasive species thrive in soil disturbed by construction and other activity. Protect newly disturbed places on your property by planting them with natives.

Control, Restore, Monitor

Invasive species outbreaks are easier to squelch when they are small and the plants are young. Some species require different methods of control, depending on how they reproduce.

  • Control invasive species. (Download a PDF outlining our recommended methods of controlling common invasive species.) Please note: Recent research has revealed harmful health effects from use of glyphosate, the active ingredient in systemic weed killers, including Roundup®. We no longer recommend using glyphosate and other herbicides. For more information about glyphosate and which products contain it, visit the National Pesticide Information Center website.
  • Dispose of invasive species so that they don't return. Plant parts that can’t re-sprout, such as woody stems and herbaceous plants without seed heads, can be left to dry and compost on the site. Materials that can re-sprout, such as Japanese knotweed stems or roots, must be burned or bagged and killed before they can be disposed of in a landfill. The same applies to plant parts with seed: Bag all seed heads and even soil containing seeds and make sure they are completely dried and dead before taking to a landfill. Download these guidelines from the University of Connecticut on disposing of invasive plants.
  • Restore native flora after rooting out invasive species to prevent re-invasion.
  • Return to the site regularly to be sure eradicated colonies stay that way.

Which Plants Are Invasive in Your State?

Check your state's invasive-plants website to find out

New England State Invasive Plant Websites
Connecticut 

Maine 

Massachusetts 

New Hampshire

Rhode Island

Vermont

“Each year, thousands of acres of forests, prairies, deserts, and aquatic areas are destroyed or weakened by aquatic and terrestrial invasive species. Invasive species impacts cost the American economy billions of dollars each year.”

—USDA Forest Service, Invasive Species Program website
Purple loosestrife

I.D. Your Plants on Go Botany

This is purple loosestrife (Lythrum salicaria), a common invasive species, which was sold in some New England nurseries until recently. Learn how to identify invasive plants and native lookalikes on our regional plant-identification tool, Go Botany.

Take Me There

“Human activity is implicated . . . in the increasing spread of invasive plants (and pests), which are adept at colonizing sites disturbed by nutrient loading, altered hydrology, and clearing, mowing, and plowing.”