Invasive plants are a major issue for Maine’s forests. Similar to invasive insects, these are plant species that are brought to the U.S. from other countries. Because they have not been adapted in our native ecosystems, they tend to become dominant and outcompete our native plant species. These plant species can cause financial harm, harm to human or animal health, and environmental harm, as defined by Executive Order 13122.
There are non-native plant species that are not necessarily invasive, and even those that have become naturalized to the U.S. because they were introduced so long ago. What sets invasive species apart is there aggressive ability to colonize large areas, outcompete native vegetation, and make long-distance jumps in location through the movement of seed. There are many species that are noxious or poisonous to humans and animals (Ex. Giant hogweed).
In forested ecosystems, these plants outcompete young trees that would be the next generation. This means that as the overstory declines and dies from age or other circumstances, there are no new trees to take their place, and what is left is large swaths of invasive plants. Essentially, entire ecosystems are changed and degraded.
The main way invasive plant species are introduced to an area is when private landowners plant them in their gardens for aesthetic purposes. While they are managed on that property through mowing and tending, landowners cannot manage the wide spread of seed through wind, water or animal dispersal. This seed travels to areas that are tended less often or not at all, where they can grow unchecked for years.
For this reason, it is strongly encouraged that Bangor residents review the list of invasive plants before purchasing from a nursery. No invasive plants are permitted to be planted in public spaces, and those already present will be removed and managed by the Forestry Division. If you already have invasive plants on your private property, it is also encouraged that they be removed as soon as possible to reduce seed sources. If you would like advice on how to best do this, please contact a member of the Forestry Division at 207-992-4514, or seek the help of a licensed pesticide applicator. You can report invasive plants to the Maine Natural Areas Program using iMap Invasives.
Some common invasive species that are planted are honeysuckle, privet, buckthorn (common and glossy), Japanese knotweed, burning bush, Japanese barberry, Japanese tree lilacs, Norway maples (trees sold as “Crimson Kings” are a Norway maple cultivar), and Bradford/Callery pear trees.
