Least Wanted Invasive Plant Species
The Plant Conservation Alliance (PCA) is a consortium of 10 federal government member agencies and over 290 non-federal cooperators representing various disciplines within the conservation field: biologists, botanists, habitat preservationists, soil scientists, etc. PCA members and cooperators work collectively to solve the problems of native plant extinction and native habitat restoration, ensuring the preservation of our ecosystem. PCA embodies the axiom: "Think Globally, Act Locally." Learn more about the Plant Conservation Alliance.
Cynanchum Louiseae Kartesz & Candhi - Milkweed Family
Black or Louis’ Swallow-Wart is a perennial, twinning herbaceous vine. The leaves are oval shaped with pointed tips and occur in pairs along the stem. The small five-petaled star shaped flowers are dark purple to almost black with white hairs. Learn more about Black Swallow-Wart (PDF).
Phragmites Australis - Grass Family (Poaceae)
Common Reed is a tall, perennial grass that can grow to over 15 feet in height. Once introduced, Common Reed invades a site, it quickly can take over a marsh community, crowding out native plants, changing marsh hydrology, altering wildlife habitat, and increasing fire potential. Learn more about the Common Reed (PDF).
Alliaria Petiolata Cavara & Grande - Mustard Family (Brassicaceae)
Garlic Mustard is a cool season biennial herb with stalked, triangular to heart-shaped, coarsely toothed leaves that give off an odor of garlic when crushed. Garlic Mustard poses a sever threat to native plants and animals in forest communities in much of the eastern and Midwestern U.S. Many native wildflowers that complete their life cycles in the springtime, of which wildlife species depend on as food sources, occur in the same habitat as Garlic Mustard. Learn more about Garlic Mustard (PDF).
Fallopia Japonica - Buckwheat Family (Polygonaceae)
Japanese Knotweed is an upright, shrublike, herbaceous perennial that can grow to over 10 feet in height. Japanese Knotweed spreads quickly to form dense thickets that exclude native vegetation and greatly alter natural ecosystems. Learn more about Japanese Knotwood (PDF).
Lepidium Latifolium L. - Mustard Family (Brassicaceae)
Perenial Pepperweed is also known as tall whitetop, giant whiteweed, perennial peppergrass, slender perennial peppercress, ironweed and other name. Plants are multiple stemmed and grow in stiffy erect masses up to 5 feet. Perennial Pepperweed is a highly invasive herbaceous perennial. It can invade a wide range of habitats including riparian areas, wetlands, marshes, and floodplains. Learn more about Perennial Pepperweed (PDF).