Invasive Species

What are invasive plants?

In Maine a plant is considered invasive if it:

1. Is not native to Maine

2. Has spread (or has the potential to spread) into minimally managed plant communities (habitats)

3. Causes economic or environmental harm by developing self-sustaining populations that are dominant or disruptive to native species

Invasive plants are a direct threat to what we value about Maine's natural and working landscapes. The aggressive growth of invasive plants increases costs for agriculture, can affect forest regeneration, threatens our recreational experiences, and reduces the value of habitats for mammals, birds and pollinators. Species like Japanese barberry and multiflora rose can form thorny, impenetrable thickets in forests and agricultural fields.

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

Controlling Invasive Plants

There are two basic approaches to the address terrestrial invasive plants: mechanical and chemical.

Types of Mechanical Removal

• Physical (hand digging or machines)

• Cultural (interplanting with natives—“suppressing invasive spread”)

• Biological (use of insects, bacteria, or other means to reduce/eliminate invasive)

Types of Chemical Removal:

• Foliar –spraying leaves

• Basal Bark—spraying bark around the base of the invasive plant.

• Cut-stump—Mechanical removal of above ground portion of plant. Then treat fresh cut stump. Chemical absorbed systemically.

Suggestions

• Identify any/all invasive plants you find on your property

• Look for insect and disease pests such as hemlock wooly adelgid (exclusive to Hemlock), Asian Long horned Beetle, Beech Leaf Disease and others; Contact Maine Forest Service if any are found.

• Pull any early detection species as soon as possible to prevent further spread. See list of widespread vs early detection plants in source list.

• Use iMapInvasives app to mark your plants. This will create a map(s) and management tracking tool for you. It is a free service managed by the State of Maine for tracking spread of invasive species.

• Create a plan to manage species identified. If more than one plant/pest is identified, and especially if they are numerous, it can seem overwhelming. Prioritize your efforts. Remember they didn’t establish overnight. It will take time to reclaim and restore your landscape.

Online Resources and Organizations for Invasive Species

• The Maine Forest Service provides information and assistance with forest insect pests and other pathogens.

• The Department of Agriculture, Conservation and Forestry, Horticulture Department has much more information on invasive plants here. The site includes recommendation for plants to replace invasive plants. Maine’s new rules regarding the sale of invasive plants are available on this website.

• Invasive Plants in Maine - Maine Natural Areas Program Invasive and potentially invasive plants list for Maine, with fact sheets for each.

• Invasive.org - A great starting place, with numerous images of each plant, and concise, thorough fact sheets on different species. The link Species is where you can find info pages on each plant and pictures as well as additional links. http://www.invasive.org/index.cfm

-Invasipedia Excellent literature summary articles on most invasive plants, more in-depth than fact sheets.

• USDA Forest Service Weed Database This site provides an in-depth profile of each invasive species, with citations to assist further research.

• Imap Invasives - Maine Natural Areas Program IMap Invasives is an invasives tracking program now available in Maine, with many tools and data resources to help communities and land owners and managers plan for invasives control. http://www.maine.gov/dacf/mnap/features/invasive_plants/imap.htm

Vermont Invasives Resources Vermont has a well-developed invasives program which includes several excellent guides.