INVASIVE! Japanese Knotweed
Japanese Knotweed is an invasive species that was introduced to the US from Asia. It is an extremely tolerant species, which thrives in full shade, high temperatures, high salinity, and draught. It is found near water sources; such as along streams and rivers, in low lying areas, waste places, and utility right-of-ways. It can quickly become an invasive pest in natural areas after spreading from cultivated gardens. It forms thick, dense colonies that completely crowd out any other herbaceous species and is now considered one of the worst invasive exotic plants in the US.
INVASIVE! Purple Loosestrife
Purple Loosestrife is a very hardy perennial plant which can rapidly infest and degrade once healthy wetlands; diminishing their value as wildlife habitat. Wetlands are the most biologically diverse, productive component of our ecosystem. Hundreds of species of plants, birds, mammals, reptiles, insects, fish, and amphibians rely on wetland habitat for their survival.
INVASIVE! Reed Canary Grass
Reed Canary Grass is a thick, perennial grass that can grow up to six feet high. It is a major threat to natural wetlands, as it can easily out compete most native species. Disturbed areas and roadside ditches are also at risk for infestation. If left untreated, the dense stands of this grass can completely take over an area, eliminating all other species and forming a large monoculture.
There are two varieties of invasive Swallow-Wort that are becoming large issues in the US; Black and Pale Swallow-Wort. Swallow-Wort is an aggressive vine that was brought to the US as an ornamental plant. It is nicknames the "dog-strangling vine" due to its ability to chose out desirable species. They can occur in a variety of habitats; from open fields to shaded woods, in either moist or dry soil.
Cattails have the ability to spread along the edge of a body of water, making entrance to the water difficult or impossible. They grow in thick stands, impeding both view of and access to the water body. Cattails are one of the most common nuisance plants we deal with. Please see our Cattail Management page to view the best options for dealing with cattails.
Buckthorn is a shrub introduced to the US from Europe in the mid 1800's, and was a very popular material for use in hedge rows. Without any natural diseases or pests to control its growth in the states, it spread quickly. It outcompetes native plants, forming impenetrable layers of vegetation. It blocks sunlight from reaching the forest floor, inhibiting the growth of any new plants. It has little value as food or shelter for wildlife or birds.
INVASIVE! Multiflora Rose
Multiflora Rose is an invasive shrub growing through most of the eastern United Stated that sometimes also grows in a vine. It's a thorny plant that outcompetes native vegetation and can easily overtake an area. A single multiflora rose bush can produce over a million seeds in a single season, which are dispersed easily by birds.
There are several species of invasive Honeysuckle bushes that you may find in New York; Amur, Japanese, and Morrow's Honeysuckle. The best way to distinguish a native honeysuckle from an invasive honeysuckle is to break open the stem. Native plants will have solid stems, while invasive will be hollow. All three of the invasive varieties have the ability to outcompete native plants and form dense stands; they are also all able to grow in many different types of areas.