Bulletin #2500, Gardening to Conserve Maine’s Native Landscape: Plants to Use and Plants to Avoid
Developed by Extension Ornamental Horticulture Specialist, Lois Stack, University of Maine Cooperative Extension with Judy Hazen Connery, Natural Resource Program Manager, Acadia National Park.
Maine’s Native Landscape
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 those species that either originated here or arrived in Maine without human intervention, perhaps thousands of years ago. Non-native species were brought intentionally for horticultural or other uses or came accidentally in ships’ ballasts, crop seed, or in soil. Some non-native plants continue to escape from cultivation and become naturalized in wetlands, lakes, woods, fields or roadsides.
Natural predators and diseases are often left behind when non-native plants are moved to new places. Therefore, their spread is uncontrolled and such non-native species as purple loosestrife, Japanese barberry, and Asian honeysuckles can become serious pests.
One long-term effect of invasive non-native species is to degrade habitat for native plants and animals. Some non-native plants choke out native vegetation, 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, invasion by non-natives could drive some species to extinction. This is why non-native plants are a major concern to people who want to protect native species and natural areas.
Plants to Avoid and Why
Most familiar nursery plants are not invasive and are appropriate for planting. However, a few popular species, including purple loosestrife and Japanese barberry, are highly invasive. A single purple loosestrife plant can produce three million seeds in a single season! Even tiny root fragments can grow into new plants. Japanese barberry is invading Maine’s forests because birds disperse its seeds over long distances. Both species are very difficult to eradicate once they become established. Other plants that have invaded southern New England, such as Callery pear and mile-a-minute vine, are poised to invade Maine, enabled in some cases by global climate change.
On January 14, 2017, the Maine Department of Agriculture, Conservation and Forestry adopted rules that prohibit the sale of 33 terrestrial plant species determined to meet the invasive plant criteria described in the rule. Additional information can be found on DAFC’s website. The 33 plants listed below are illegal to import, export, buy, sell or intentionally propagate after December 31, 2017. The ban includes all cultivars, varieties, and hybrids of these plants.
What Can You Do to Help?
- Promote native plants by refusing to purchase or transplant them.
- Grow plants that do not “jump the fence” or escape from your garden.
- Try growing some 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 them in a way that does not allow them to spread to a new site.
Urge your garden center managers to expand their selection of propagated native plants.
Looking for Native Plants at Your Garden Center
Native plants are well adapted to Maine’s climate and are therefore hardy. Most plants in the Native Plant Recommendations are available at local garden centers, where professionals can help you with plant selection. Ask if their native plants are nursery-propagated. Collecting plants, cuttings, seeds, or sods from the wild can devastate natural populations. If the nursery cannot guarantee that its native plants are nursery-propagated, purchase your plants elsewhere.
Avoid collecting native plants from wild areas; some species are vulnerable to over-collecting. Also, leaving open disturbed soil in natural areas can allow those sites to be colonized by weedy or invasive species.
The Maine Department of Agriculture, Conservation and Forestry Horticulture Program’s Invasive Plants website describes and lists invasive exotic plants that present threats to native Maine terrestrial habitats, their history and alternatives to invasive plants.
Key to Light and Moisture Abbreviations
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
Native Plant Recommendations
This 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.
© 2003, 2017, 2020
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