Invasive Species

  • Bittersweet Invasive
Invasive Plants & Pests

An invasive is a plant or animal that is not native to a particular ecosystem, whose introduction does or is likely to cause economic or environmental harm, or harm to human health. It is capable of moving aggressively into an area, monopolizing light, nutrients, water, and space to the detriment of native species.

Below are resources you can use to identify, map, report and manage invasive plants and pests.

Invasive Pests

There are many different damaging insects and diseases that currently threaten New Hampshire's towns and forests. Most are not native to North America and can spread quickly. They can pose a serious risk to trees and forests. Learn to identify and report invasive forest pests through NHBugs, a collaboration of forest health agencies in NH.


Invasive Plants

Many familiar plants in our fields and along roadsides are not native to New Hampshire. While the majority cause no harm to forests, some do and are considered invasive plants. Invasive plants can reduce biodiversity, imperil rare species, reduce wildlife habitat, degrade water quality, reduce forest production and cause human health problems. Below are resources to help identify, map, report and management invasive plants.

Invasive Plants

Garlic Mustard Flowers

Learning to identify invasive plants is an important first step you can take to help stop their spread. Most invasive plants can be easily recognized with a few small tips. There are several invasive plant species that are considered early detection, meaning the species isn't well established in the state and we have an opportunity to stop it.

flowering honeysuckle
Guide to NH's Upland Invasive Species

Detailed descriptions and photos of invasive plant species in NH, maintained by the NH Department of Agriculture Markets & Food Plant Industry Division.

Get the Guide

black swallow-wort
Early Detection Invasive Plant Videos

Videos explaining how to identify four early detection species: Perennial Pepperweed, Tree of Heaven, Black Swallow-Wort and Garlic Mustard.

Watch Videos

glossy buckthorn with berries
Spotlight on NH's Common Invasives

UNH Extension blogs on how to identify many of the most common invasive plants in NH.

Spotlight Blogs

Bittersweet Vine
Mapping & Reporting

Figuring out where and how many invasive plants are in an area is an essential step to determining your management strategy. It is also important to report early detection species through EDDMapS, our state reporting system, so our state invasive species coordinator can act on the reports.


EDDMapS is the online service NH uses to report and track invasive species.

Report It

invasive management
Management & Control

There is no one size fits all management strategy for invasive plants. Effective strategies depend on the species of plant and the goals of the property owner/manager. Below are a variety of resources to help you decide how to manage invasive plants.

Pulling Invasive Plants
Picking your battles

A resource from NH Fish and Game to help prioritize invasive plant management.

Get the Guide

Wild Parsnip Control
Control Methods

A collection of control resources organized by plant species or control method.

Explore the Resources

Invasive Pile
Disposing Invasive Plants

To prevent further spread, its very important to properly dispose of invasive plants.

Get the Fact Sheet

Native Alternatives

A fact sheet of native plant alternatives to invasive plants.

Get the Resource

community action
Community Action

Working with your community to tackle invasive plants is a great strategy. You can collaborate with other volunteers or town groups to organize managing invasives in your community.

Stewardship Tool Library
Tool Library

Borrow tools for free at one of two stewardship tool libraries in NH

Borrow Tools

Nature Groupie
Nature Groupie

Post your community workday to Nature Groupie to help spread the word.

Nature Groupie

Invasives Stewardship Guide
Invasives Plants Training Guide

A collection of resources for community education on invasive plants in NH.

Get the Guide

Get Help: Forester
Professional Assistance

There are a variety of Natural Resource Professionals who can help provide guidance on property goals and planning, and advice on control strategies.

County Forester
County Forester

Extension Natural Resource Professionals can help by visiting your property

Forestry & Wildlife Staff List

Licensed Forester
Directory of Licensed Foresters

A directory of foresters licensed in New Hampshire, including licensed pesticide applicators.

NH Licensed Foresters

Invasives Academy
NH Invasives Academy

Held annually, the NH Invasives Academy is a training about management options for terrestrial invasive plants. 

Check the Extension Calendar for Upcoming Trainings

Pesticide Safety Education and Applicator Licenses

Pesticide Certification

UNH Extension's Pesticide Safety Education Program provides educational resources and training programs for private and commercial pesticide applicator certification and online recertifcation. Our programs promote sound decision-making and protection of people and the environment. 

Learn more about Pesticide Safety Education

Perennial Pepperweed Partnership


Pepperweed (Lepidium latifolium) is a relatively new invasive plant to Maine and New Hampshire, though it is well established just to our south in Massachusetts.  UNH Extension is working with partners to map Pepperweed in Maine and New Hampshire and work towards eradication.

Learn more about Pepperweed

Spotlight on NH Invasives

Purple Loosestrife

From UNH Master Gardeners, a series of blogs on how to identify and control common invasives in NH.

Spotlight Blogs


Keep an eye out for invasive insects this summer.
Check your pool filters for invasive insects this summer. Learn More
Pull by Hand April-June before it goes to seed
Garlic mustard is a pernicious non-native plant which: 1. Releases sinigrin, preventing the growth of other plants by disrupting a beneficial fung... Learn More
As the weather warms and our days stretch longer and brighter, we begin to see and hear the bustle of the natural world picking up all around us. The ... Learn More


Are you planning a stewardship or invasive plant control project in New Hampshire? Use EDDMapS on your computer, smartphone or tablet to map invasive ... Learn More
Video: How to use the free EDDMaps Website and Mobile App to learn more about invasive species, their distributions and participant in tracking and ma... Learn More
Identification tips and basic control methods for some of NH's invasive plants: Glossy Buckthorn, European Barberry, Japanese Honeysuckle, Purple... Learn More


August 29, 2024 | 9:00am - 12:15pm
Join Extension Foresters Mike Gagnon and Dode Gladders, for this hands-on workshop focused on using herbicides to manage upland non-native invasive plant species in New Hampshire. The first half of…