The Conservation Commission is spearheading a multi-year project to remove invasive plants and restore native habitat on town property. Our first sites are Rotary Park and Rogers Pond. They have significant stands of Japanese knotweed, as well as multiflora rose and Asiatic bittersweet, among other invasives. The goal for this project is to control the spread of these species before they overwhelm our native ecosystems. 

Read below to learn more and find out how you can help.

What are these plants?

There are a large number of invasive plant species in Maine. We are targeting the following invasive species because they are particularly aggressive and widespread.

1. Japanese Knotweed 
   Japanese Knotweed is a highly aggressive perennial that grows in dense stands along roadsides, riverbanks, and disturbed areas. It quickly crowds out native plants, creating monocultures that reduce habitat diversity. Its extensive root system also causes significant erosion, especially along riverbanks, increasing the risk of flooding and threatening water quality.

When Japanese knotweed grows near man-made structures such as bridge abutments, roads, sidewalks, parking lots, and foundations, it can damage their structural integrity. It can also damage subsurface drainage, underground conduits and septic systems. 

2. Asiatic Bittersweet 
   Asiatic Bittersweet is a woody vine that has become one of the most invasive species in Maine, particularly in forested areas and along roadsides. Bittersweet climbs up trees, choking them and preventing light from reaching the tree canopy. The weight of the vine can also break branches, further weakening the host tree. Over time, this vine kills trees, reduces forest regeneration, and drastically alters the structure of Maine’s forests. Bittersweet produces bright orange berries that are dispersed by birds, helping the plant spread even further.  

3. Multiflora Rose
   This woody shrub can produce up to a million seeds per year, which remain viable in the ground for up to 20 years. It forms thickets of thorny vines that exclude native plants. It thrives in a variety of habitats, including dense woods, open fields and stream banks. Birds eat the fruits and distribute the seeds widely, making it a large threat to our native ecosystems.
   

4. Shrubby Honeysuckles ( Bella, Morrow, Tartarian)
    Invasive varieties of this shrub have become widespread in Maine’s forests and disturbed areas. They grow rapidly and form  dense thickets that shade out native understory plants, reduce biodiversity and alter forest structure.

What can I do to help?

Sign up to volunteer!

The Conservation Commission is holding volunteer days at Rogers Pond. We will be removing Japanese knotweed and other invasive plants from the park. Sign up to get notices of our volunteer days. It not only helps your community, but you will learn to identify invasive plants and learn good removal strategies for your own yard.

The Kennebunk Land Trust also has invasive plant removal projects.  

Identify invasive plants in your yard and remove them 

Regular monitoring and removal is key to preventing the spread of invasive species. When you remove invasive plants in your yard, you are not only making room for native plants and wildlife, but you’re keeping the plants from spreading to your neighbors’ yards, and, significantly, to our forests, riverbanks and wetlands. 

Removal Strategies

1. Manual Removal: For small infestations, hand-pulling can be effective. Make sure to remove the entire root system to prevent regrowth. Wear gloves to protect your hands from any irritants.
2. Cutting and Mowing: For larger populations, repeatedly cutting the plants back can weaken the plants and help control their spread. This method, however, often requires consistent cutting over a period of years, as many invasive species can resprout from cuttings. If mowing, the lawn mower must be cleaned thoroughly afterward to reduce the risk of spreading the invasive elsewhere. 
3. Herbicide Application: In cases of severe infestation, targeted herbicide use may be necessary. It’s crucial to select a product and application method that minimizes harm to surrounding native plants, and to follow all application guidelines carefully. Do not use more than is specified on the label (the label is the law).  Applying herbicides in early spring or late summer when the plants are not actively growing is generally most effective.
4. Mulching and Replanting: After removing invasive plants, consider applying mulch to suppress regrowth and prevent new invasions. Additionally, replanting with native species can help restore balance to your yard and provide habitat for local wildlife.

More resources: 

• Maine Natural Areas Program 
• Maine Invasive Species Network