Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid
Originally developed by Extension Ornamental Horticulture Specialist, Lois Stack, University of Maine Cooperative Extension with Judy Hazen Connery, Natural Resource Program Manager, Acadia National Park.
Reviewed and updated by University of Maine Cooperative Extension staff, 2023and 2025.
Maine’s landscape offers spectacular variety, with ocean beaches, lakes, rivers, mountains, fields, and forests. Maine is locally influenced by both coastal and inland weather patterns. This creates relatively mild areas, and areas that are almost arctic, all within the state’s 300-mile length and 200-mile width. Maine rises from sea level to over 5,000 feet in elevation at the top of Mount Katahdin. This wide range of elevation results in a diversity of habitats including flat sandy plains, rolling hills, rounded summits, and craggy mountains with sheer cliffs. Maine’s forests vary from spruce and fir near the coast to hardwoods in the western hills, and mixed hardwood/softwood forests in the North. More than 100 types of habitats have been identified with about 1,500 native plant species spread across the state’s varied landscape.
What Are Native Versus Non-native Plant Species, and Why Should I Care?
Native plants are species that either originated or arrived in a specific region without human intervention, perhaps thousands of years ago. Non-native species were brought intentionally for horticultural or other uses, or came accidentally in ships’ ballast, crop seed or in soil. Some non-native plants continue to escape from cultivation and become naturalized in wetlands, lakes, woods, fields, or roadsides.
Native plants are essential to local ecosystems because they have co-evolved with native insects and wildlife, often serving as their primary or exclusive food source. As habitat and food resources for native insects, birds, and mammals continue to shrink, incorporating native plants into your landscape helps support biodiversity by creating vital food corridors and habitat. Biodiversity is crucial for maintaining resilient ecosystems and sustaining life on Earth.
In addition to their ecological benefits, native plants enhance Maine’s natural landscape, one of our most important resources, with their subtle beauty and are often well-adapted to challenging site conditions.
What are Invasive Plants and Why Should I Care?
According to the Maine Natural Areas Program, “[a]n invasive plant is defined as a plant 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. There are currently approximately 2,100 plant species recorded from Maine. Approximately one-third of those are not native. Of those plants that are not native, only a small fraction is considered invasive, but these have the potential to cause great harm to our landscape.”
Invasive plants are a threat because they typically have one or more of the following survival strategies:
A lack of natural predators and diseases. These population control mechanisms are often left behind when non-native plants are moved to new places.
Some have the capacity to produce copious amounts of seed. For example, a single purple loosestrife plant can produce three million seeds in a single season!
Efficient seed dispersal mechanisms/adaptations can allow invasives to move over long distances. Japanese barberry and burning bush are two examples of plants invading Maine’s forests because birds consume the fruit and deposit the seeds far from the parent plant.
Leaves may emerge earlier in the season and/or remain later into the fall compared to their native counterparts, lending competitive advantage or shading competitors. This is easily noticeable in the spring when spotting non-native honeysuckles or burning bush growing along roadsides.
Lastly, many invasives have the ability to grow in a wide range of sun and soil conditions which may allow them to outcompete their native counterparts.
When invasive species degrade habitat for native plants and animals, they diminish the availability of food and habitat for wildlife and alter the behavior of native animals such as pollinators, plant-eating insects and fruit-eating birds. Unchecked, invasives could drive some species to extinction. This is why invasive plants are a major concern to people who want to protect native species and natural areas.
Plants to Avoid
The Maine Department of Agriculture, Conservation and Forestry (DACF) Horticulture Program, in collaboration with a stakeholder committee, maintains three invasive plant lists.
The Do Not Sell Invasive Plant List includes terrestrial plant species that are “illegal to import, export, buy, sell or intentionally propagate for sale.”
A Watch List has been curated to highlight plants that don’t currently meet the criteria to be included in the “Do Not Sell List,” but have raised enough concern to warrant continued evaluation in the future. Plants in this list can be sold without restrictions.
Plants of Special Concern is a designation established for plants that “may be invasive in some habitats and alternative plants should be considered.” Plants in this category can still be sold, but will require special labeling.
Lastly, the DACF Maine Natural Areas Program maintains an Advisory List that is intended for educational and land management purposes. This is not a regulatory list, but is a helpful tool for assessing risks associated with plants that have not fallen under the scope of the current regulations.
Be familiar with the Do Not Sell Invasive Plant List, Watch List and Plants of Special Concern. Occasionally, roadside plant sales, garden centers and even online vendors are not fully in compliance with the law, so it’s important that consumers play an active role in knowing what plants should be avoided.
Gently educate “generous” gardening friends whom you may witness sharing invasive plants with others.
Grow plants that do not “jump the fence” or escape from your garden.
Try growing native plants as ornamentals and as food for birds and pollinators.
Eliminate invasive non-natives from your yard and garden. Remove the plant, including roots, and dispose of it in a way that does not allow it to spread to a new site.
Urge your garden center managers to expand their selection of propagated native plants.
While you’re shopping, ask the vendor if their native plants are nursery-propagated. If the nursery cannot guarantee that its native plants are nursery-propagated, purchase your plants elsewhere.
Collecting plants, cuttings, seeds or sods from the wild can devastate natural populations. Some species are vulnerable to over collecting and some simply will not survive being transplanted. Also, leaving open disturbed soil in natural areas can allow those sites to be colonized by weedy or invasive species.
The following is by no means a comprehensive list of native plants. Instead, it’s a selection of species that are relatively easy to find and have attributes that make them well-suited for managed landscapes. For additional plant lists, visit our Pollinator-Friendly Garden Certification program page for a curated list of native plant resources.
Key to Light and Moisture Abbreviations
Light:
F=full sunlight P=partial shade S=shade
Moisture:
H=hydric; wet, periodically or often inundated by water M=mesic; moist, adequate soil moisture all year S=sub-xeric; moist to dry, seasonally moist but periodically dry X=xeric; dry, little soil moisture retention, excessively well drained
The botanical names in this plant list are consistent with those found in: Haines, A. 2011. Flora Novae-Angliae: a manual for the identification of native and naturalized higher vascular plants of New England. Yale University Press.
This original publication was made possible by:
Friends of Acadia
Garden Club Federation of Maine
Josselyn Botanical Society
Maine Natural Areas Program
Maine Department of Conservation
Maine Department of Agriculture
Maine Landscape and Nursery Association
Maine Outdoor Heritage Fund
National Fish and Wildlife Foundation
National Park Service
Plant Conservation Alliance
The Nature Conservancy
University of Maine Cooperative Extension
University of Maine Horticulture Club
U.S.D.A. Forest Service
Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
Call 800.287.0274 (in Maine), or 207.581.3188, for information on publications and program offerings from University of Maine Cooperative Extension, or visit extension.umaine.edu.
In complying with the letter and spirit of applicable laws and pursuing its own goals of diversity, the University of Maine System does not discriminate on the grounds of race, color, religion, sex, sexual orientation, transgender status, gender, gender identity or expression, ethnicity, national origin, citizenship status, familial status, ancestry, age, disability physical or mental, genetic information, or veterans or military status in employment, education, and all other programs and activities. The University provides reasonable accommodations to qualified individuals with disabilities upon request. The following person has been designated to handle inquiries regarding non-discrimination policies: Director of Equal Opportunity and Title IX Services, 5713 Chadbourne Hall, Room 412, University of Maine, Orono, ME 04469-5713, 207.581.1226, TTY 711 (Maine Relay System).
Light:
Moisture: 
