- Purple loosestrife (Lythrum salicaria) (pictured) is a tall perennial herb native to Europe. It produces beautiful pink and purple flowers, and was bred artificially by horticulturists in the mid 1900s as an ornamental. In the US and Canada, it has become a noxious and prolific invasive. Its typical habitat includes cattail marshes, sedge meadows, and bogs. It also occurs along ditch, stream, and riverbanks, lake shores, and other wet areas. In these habitats, purple loosestrife forms dense, monospecific (single-species) clusters that can grow to thousands of acres in size, displacing native plant species and eliminating open water habitat. The loss of native species and habitat diversity is a significant threat to wildlife, including birds, amphibians, and butterflies, that depend on wetlands for food and shelter.
- The common reed (Phragmites australis) is a tall, stoloniferous grass species that is native to parts of the continental U.S., although it is hypothesized that the more invasive strains were introduced from Europe. It grows in marshes and swamps, on banks of streams and lakes, and around springs. It is considered a noxious weed in Connecticut due to the fact that it crowds out native species.
- Hydrilla, also sometimes called waterthyme (Hydrilla verticillata), is a slender perennial freshwater herb. It is believed to be native to parts of Africa and south and southeast Asia. It is considered a noxious invasive weed throughout the US. A map of its presumed range in the U.S. can be found in the USDA PLANTS database. Additional information about its global range can be found on the Encyclopedia of Life website.
For a more detailed list of invasive aquatic and wetland plants, see Connecticut’s Invasive Aquatic and Wetland Plants Identification Guide or UConn’s Connecticut Invasive Plant Working Group’s (CIPWG) plant list.