What’s the difference between a “weed” and an “invasive plant”? A weed is simply a plant growing in a place where it’s not wanted. It might be a problem locally, but it generally doesn’t spread to become a large-scale problem in natural areas.

An invasive plant is a non-native plant with very high reproductive potential and the ability to establish across long distances (for example, it might produce seeds that can spread by wind or by animals). An invasive plant can become established in natural areas, and disrupt natural communities by outcompeting native plants.

Why are invasive plants suddenly a problem?
The invasive plant problem is not new, but the problem is accelerating. Due to a history of low intensity development and perhaps isolated watersheds, Maine’s landscape has not been ravaged to the same degree as most other New England states. However, our good fortune will be short-lived if invasive plants continue to spread unchecked through our state.

Where do invasive plants come from?
About two-thirds of known invaders have been imported for ornamental and landscape plantings. These species include many of the Northeast’s most troublesome plants: Japanese barberry, oriental bittersweet, Russian olive, Eurasian milfoil, purple loosestrife, and others. Other species have arrived as stowaways: Japanese stilt grass is used in packaging from Japan, and mile-a-minute weed is transported in soil.

What problems do invasive plants cause?
Invasive plants outcompete native species and agricultural crops, causing billions of dollars of damage each year. They affect forests, wetlands, lakes, streams, croplands, and pastures, and degrade many of our sensitive natural habitats. They grow rapidly, multiply, and spread to unmanageable levels in short periods of time.

Invasive species are the second greatest threat to global biodiversity, after loss of habitat. Invading plants outcompete native species for sunlight, nutrients, and space. They change animal habitat by eliminating native foods, altering cover, and destroying nesting opportunities. Some invaders are so aggressive that they leave no room for our natives.

Invasive plants threaten Maine’s natural and working landscapes. Their aggressive growth degrades our recreational experiences. Species like Japanese barberry and multiflora rose can form thorny, impenetrable thickets in forests. Other invasive plants choke waterways, limiting their use. Invaders increase the costs of agriculture and affect forest regeneration. And, these species mar the natural beauty of our regionally distinctive landscape.

Are invasive plants being controlled?
Controlling invasive plants is a challenge. Every year, more and more money is needed to combat them. Vermont has spent millions of dollars trying to clear its waterways of just two invasive plants species, Eurasian milfoil and water chestnut. Florida spends $30 million every year managing invasive plants. Costs in Maine are creeping up as we work to control invaders in our state and national parks. Maine’s Department of Environmental Protection and Department of Inland Fisheries and Wildlife now spend over $1 million each year on management and prevention of infestations of aquatic weeds … and we are just getting started.

What can you do?
Prevention is the key. Until recently, alien plants have benefited from our slow reaction to their damaging impacts. Invaders that are already widespread, like purple loosestrife, are here to stay. But species that have not reached Maine yet, like porcelain berry and mile-a-minute weed, need to be stopped. The damage invasive plants can do is well documented in other New England states. Learn about invasive plants, and avoid them. Your actions can make a difference. Don’t help invaders get around in Maine.

• When buying plants or moving them from place to place, consider whether they are likely to escape. Plants advertised as fast growing, prolific, and tolerant of many growing conditions are often the ones that become invasive. Maine won’t look like Maine anymore if the plants dominating our landscape are all from away.
• Verify that plants you buy for your yard or garden are not invasive. Ask your local garden supplier to stock more native species.
• Replace invasive plants in your garden with non-invasive alternatives.
• When boating, clean your boat thoroughly before transporting it to a different body of water.
• Volunteer at your local park, refuge or other wildlife area to help remove invasive species. Help educate others about the problem.
• Learn which plants are problematic in Maine and tell your state representatives that you care about the future of Maine’s natural landscape.
• Our natural landscape is precious. Its future depends on the choices we make.

Maine Natural Areas Program and University of Maine Cooperative Extension.

By: USGS National Wildlife Health Center
White-nose syndrome (WNS) is an emergent disease of hibernating bats that has spread from the northeastern to the central United States at an alarming rate. Read More »


By: ANSTF Strategic Plan Committee
Aquatic nuisance species (ANS) are nonindigenous species that threaten the diversity or abundance of native species, the ecological stability of infested waters, and/or any commercial, agricultural, aquacultural , or recreational activities dependent on such waters. ANS include  nonindigenous species that may occur within inland, estuarine, or marine waters and that presently or potentially threaten ecological processes or natural resources. The term ANS is often used interchangeably with aquatic invasive species, the preferred term of Federal and State managers. An aquatic invasive species is defined as a species not native to the ecosystem under consideration whereby introduction of this species does or is likely to cause economic or environmental harm or threaten human health.
Read More »


By: Mandy Tu, Callie Hurd & John M. Randall
Invasive non-native plants are a serious threat to native species, communities, and ecosystems in many areas around the world. They can compete with and displace native plants, animals, and other organisms that depend on them, alter ecosystem functions and cycles significantly, hybridize with native species, and promote other invaders. The good news is that many plant invasions can be reversed, halted or slowed, and in certain situations, even badly infested areas can be restored to healthy systems dominated by native species. In most instances this requires taking action to control and manage those invasive plants. This handbook provides you with detailed information about the tools and techniques available for controlling invasive plants, or weeds, in natural areas. Whenever possible, language familiar to natural area managers is used, and unfamiliar terms and jargon borrowed from other fields are defined.
Read More »


By: R.J. Pawlitz and K.D.David
The U.S. Geological Survey (USGS) Nonindigenous Aquatic Species (NAS) Program monitors, analyzes, and records sightings of non-native (introduced) aquatic species through-out the United States. The program is based at the USGS Southeast Ecological Science Center in Gainesville, Florida. Read More »


By: Daniel Simberloff, Ingrid M Parker, and Phyllis N Windle
Introduced species represent an accelerated global change, and current efforts to manage them, though effective in particular situations, are not controlling the general problem. In the US, this failure is the result of insufficient policy, inadequate research and management funding, and gaps in scientific knowledge.
Read More »


By: U.S. Fish & Wildlife Service
Injurious wildlife are mammals, birds, amphibians, reptiles, fish, crustaceans, mollusks and their  offspring or gametes that are injurious to the interests of human beings, agriculture, horticulture, forestry, wildlife or wildlife resources of the United States. Read More »


By: U.S. Fish & Wildlife Service
The negative consequences of invasive species are far-reaching, costing the United States billions of dollars in damages every year. Compounding the problem is that these harmful invaders spread at astonishing rates. Such infestations of invasive plants and animals can negatively affect property values, agricultural productivity, public utility operations, native fisheries, tourism, outdoor recreation, and the overall health of an ecosystem. Read More »


By: M. Brooks and M. Lusk
Fire management can help maintain natural habitats, increase forage for wildlife, reduce fuel loads that might otherwise lead to catastrophic wildfire, and maintain natural succession. Today, there is an emerging challenge that fire managers need to be aware of: invasive plants. Fire management activities can create ideal opportunities for invasions by nonnative plants, potentially undermining the benefits of fire management actions. This manual provides practical guidelines that fire managers should consider with respect to invasive plants. Read More »


This 40-page document provides detailed information on the biology of wild pigs, how to recognize their presence, the type of damage they can cause to agriculture and natural areas and a wide range of management techniques, including hunting.  It applies to just about anywhere in the U.S. where wild pigs are found. Read More »


This brief 2-pager tells which reptiles make good pets and which do not, as well as advice on care and an explanation for why responsible pet owners do not release their pets into the environment. Read More »

Nearly 1500 species of native plants are part of what makes Maine a unique place. Native plants—also called indigenous plants—are those that either originated here, or arrived without human intervention.

We have brought many nonnative plants—exotic or alien plants—to Maine as food, fiber, and landscape plants. In addition, we have introduced some nonnative plants unintentionally, as contaminants in crop seed, in the soil of other plants, and in ships’ ballast.

Why are native plants important?
Native plants form the historical basis of our landscape, provide food and habitat for animals, and serve as natural sources of food, fiber, and other products.

Native plants can serve several functions in the landscape. Native shade trees such as red oak and white ash, and evergreens like white pine and eastern hemlock, form the structure of the natural landscape. Fruiting shrubs such as black chokeberry, gray dogwood, and winterberry provide food for wildlife and add seasonal interest to the landscape. Groundcovers like bearberry and creeping juniper can be planted to preserve a sense of open space while reducing the size of lawns. Native perennials and ferns can be used in woodland gardens.

• Avoid disturbing natural areas or clearing land of native plants.
• Purchase only propagated native plants, not those dug from the wild.
• Do not purchase or plant invasive nonnative species.
• Discuss your concern about invasive nonnative plants with your local nursery or garden center professionals. Encourage them not to sell these plants, but rather to expand their offerings of propagated native plants.
• Learn to identify plants, so that you can learn more about them and determine if they have invasive tendencies. You can take samples of plants to local nurseries and garden centers for identification, or to your local county Extension office.
• Learn to identify and control invasive nonnative plants in your landscape.
• Get involved in community efforts to control invasive nonnative plants on public lands.

Lois Berg Stack, Extension professor and ornamental horticulture specialist

Find a nursery that sells plants native to Maine »»

A 2008 Farm Bill provision allows for a 25% Deduction for Endangered Species Recovery Expenditures. Read More »


This brief 2-pager tells which reptiles make good pets and which do not, as well as advice on care and an explanation for why responsible pet owners do not release their pets into the environment. Read More »


Bats, still a required decor component for Halloween, are increasingly recognized as the important creatures that they are.  Bats are important predators and pollinators in ecosystems throughout the world.  The benefits they provide humans are substantial - both in terms of controlling insect pests and pollinating economically important crops.
Read More »


According to the US Fish and Wildlife Service, endemic species are native species that are confined to a certain region or having a comparatively restricted distribution.  For example, the Joshua Tree is endemic to the Mojave Desert.  In other words, endemics, wherever they are located, are unique to their region.  In general, the greater the isolation or specialized nature of the habitat, the more numerous the endemics.  Thus, according to Britannica Encyclopedia online, species on remote oceanic islands tend to be almost 100% endemic. Read More »


Do you want to connect your audiences to conservation messages but don’t know where to start? Conservation plans, based on extensive biological research, will help prioritize your efforts. 

This resource sheet will help you:

• Link your education programs to priorities in bird conservation plans; 
• Find relevant bird conservation plans in your area of focus; 
• Extract key information to guide education program development; and 
• Involve scientists in the development of your education programs.

This is an Invasive Species Element Stewardship Abstract, prepared by The Nature Conservancy to assist their land stewards and other land managers in managing invasive species. An Element Stewardship Abstract always contains information on the origins and range of the species, as well as its biology and, most importantly, options for management, control and habitat restoration. This abstract addresses the nuisance aquatic species hydrilla.

Read More »


A Prescribed Fire Association is a group of landown- ers and other concerned citizens that form a partnership to conduct prescribed burns. Prescribed burning is the key land management tool used to restore and maintain native plant communities to their former diversity and productivity for livestock production and wildlife habitat. Native prairies, shrublands, and forests supply the majority of livestock forage and much of the wildlife habitat in the U.S. Without fire, many native plant communities become dysfunctional and unproductive. Research has clearly shown that there is no substitute for fire.  Read More »


This 40-page document provides detailed information on the biology of wild pigs, how to recognize their presence, the type of damage they can cause to agriculture and natural areas and a wide range of management techniques, including hunting.  It applies to just about anywhere in the U.S. where wild pigs are found. Read More »


Gives an overview of prevention techniques for live fish, shellfish, ornamental fish and invertebrates, aquatic plants, marine shrimp and freshwater prawns.
A list of all Southern Regional Aquaculture Center factsheets (more than 150) are available at https://srac.tamu.edu/index.cfm/event/viewAllSheets/ Read More »


Discusses pathogens and parasites, genetic alterations, and genetically modified organisms.
A list of all Southern Regional Aquaculture Center factsheets (more than 150) are available at https://srac.tamu.edu/index.cfm/event/viewAllSheets/ Read More »


A must-read for any responsible aquaculturist contemplating non-native species production.
A list of all Southern Regional Aquaculture Center factsheets (more than 150) are available at https://srac.tamu.edu/index.cfm/event/viewAllSheets/ Read More »


Strategies and cost estimates for various forms of frightening programs and exclusion ro barrier methods of control.
A list of all Southern Regional Aquaculture Center factsheets (more than 150) are available at https://srac.tamu.edu/index.cfm/event/viewAllSheets/ Read More »

BMPs oriented more specifically toward farming & agriculture, wildlife habitat and energy efficiency are also available on this site.

The following news articles are provided by the Google News service and do not reflect the views or imply an endorsement by the Maine Conservation Center and its affiliates. We cannot guarantee the relevance of the content of this page or any links that may be followed from the articles herein.

Garden in the Woods opens new activity area Framingham TAB From this base, 35 staff and more than 700 volunteers work throughout New England to monitor and protect rare and endangered plants, collect and preserve seeds to ensure biological diversity, detect and control invasive species, conduct research, and ... and more »

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University of Delaware

Annual dinner recognizes last year's Plastino Scholars, welcomes 2013 cohort University of Delaware Ian Guthoff from Wappingers Falls, N.Y., a history and political science double major with a minor in economics, will travel to six national parks on the East Coast, creating individual projects at each, from invasive species removal in a park on Maine ...

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Press Herald

Eradication push gets cat lovers' backs up Press Herald New Zealand has already cleared more than 80 of its 220 offshore islands of invasive species. But Morgan's target, Stewart Island, is 15 times larger than any other that has been made pest-free, so the effort would be closely watched by ... and more »

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Press Herald

Scientists envision changing forests Press Herald The Maine Forest Service is again conducting an extensive survey for EAB using purple sticky traps. The Division of Plant and Animal Health, the Penobscot Nation, and the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant ... Climate change expected to impact Maine's forestsMorning Sentinel all 2 news articles »

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The Forecaster

Real-world education: Portland school a model for Expeditionary Learning The Forecaster Throughout the school year, students at King take the traditional school-day lessons of reading, writing, art and math, and use them to address real-world problems, such as energy, pollution and invasive species. "It's a combination of the ... Grant ...

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Woman who calls koi 'my Prozac' wins conditional permit Press Herald AUGUSTA - A Harpswell woman who describes her pet koi as a substitute for Prozac told a judge Wednesday that Maine is too strict when it comes to laws regulating the fish. The state considers the fish an invasive species that must be kept out of Maine ... and more »

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Alliance offering paddling trips this summer Foster's Daily Democrat During the morning workshop, from 9 a.m. to noon, attendees will learn about invasive aquatic species of concern in Southern Maine and New Hampshire and basic identification techniques — with a PowerPoint presentation and some live plant samples.

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Morning Sentinel

Nonprofit triples size of LakeSmart water protection program in single year Morning Sentinel The practice helps keep phosphorus from entering the water. Phosphorus, a common ingredient in fertilizer that also is found naturally in animal waste, is valuable to farmers and gardeners because it stimulates plant growth. ... In 2012, the department ... and more »

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In the Northeast, forests with entirely native flora are not the norm ... EurekAlert (press release) The study across two dozen states from North Dakota to Maine can help land managers pinpoint areas on the landscape where invasive plants might take root. "We found two-thirds of more than 1,300 plots from our annual forest inventory had at least one ... and more »

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WLBZ-TV

Maine woman seeks to keep prohibited exotic fish WLBZ-TV Assistant Attorney General Mark Randlett told the Kennebec Journal that koi are considered an invasive species that could compete with and threaten native fish populations should they be released into the wild. Justice Donald Marden is expected to rule ... and more »