Invasive Species

Invasive plant and flower species are species that have come here from other parts of the globe. They have not evolved to form symbiotic relationships with our local plants and animals. Some of them, such as Queen Anne’s lace and dandelions, have become naturalized—that is, they now fit into the ecosystem without causing too much havoc. But many species, especially plants, have invaded Westchester with devastating results.

What Harm Do They Do?

Invasive plants grow rapidly, crowd out native species, and are enormously difficult to eradicate. Because they have not evolved here, they do not provide food and habitat for local birds, butterflies, bees, and beneficial insects. In fact, some are downright lethal to these creatures. And once they take over, as they have in most of our parks and natural areas, they rob the landscape of plants that could otherwise provide sustenance to pollinators and the animals that sustain them.

How Did Invasive Plants Get Here?

Ever since the first Europeans came to this continent and brought plants from home, we’ve been challenged by invasive species. Today, Westchester’s location so close to New York City, gateway to the world, has made us especially vulnerable to invasive species that have come in as seeds through packing crates, vehicles, and people’s clothing.

Our own backyards have been another source. By using traditional landscaping methods, consisting of mostly non-native lawn and ornamental plants, we have unknowingly contributed to the problem. Our plants have escaped into the wild. The English ivy we prized is now a menace in the woods. The Norway maples we were encouraged to plant have spread to natural areas where their early leaves shade out and kill native plant understory. The Asian bittersweet whose red berries looked so gorgeous in fall are now matting and strangling trees all up and down our parkways.

What can we do to get rid of them?

First, make sure they're not in your garden and you are not planting them this Spring! See the list of invasive species on this page and check out these additional resources that provide details and photos, including “lookalike” plants, often native varieties, that can be confused with the invasive plant.

Lower Hudson PRISM



Second, join the local effort to remove these from our ecosystem.

See the following for on-site training for removing invasive plants and how you can volunteer. You can join a group or bring your own group for a day of service outdoors!

Westchester Parks Foundation

Jay Heritage Center

Bronx River Parkway Reservation Conservancy

Invasive Plants to Avoid in Your Garden

Some of these plants are still being sold in nurseries—do not purchase them! If you have them in your garden already, because they were either planted or entered from other areas, it’s best to remove them. Be sure to remove them safely, to avoid injuring yourself or others, or inadvertently spreading the seeds.

Invasive Trees:

Norway maple

Tree of Heaven


Japanese Angelica Tree

Invasive Vines:

Porcelain berry vine

Oriental bittersweet vine

English ivy

Kudzu vine



Invasive Bushes:


Japanese barberry

Japanese knotweed

Burning bush (also called Winged euonymous)

Siebold's viburnum

Multiflora rose


Giant hogweed: rare in our area but extremely dangerous; the toxic sap causes blindness and disfigures skin

Invasive Flowers and Grasses:

Japanese stiltgrass

Garlic mustard


Phragmites australis (reed grass)

Lesser calandine—a yellow spring flower that carpets woodlands; all over Bronxville

Photo credit - Jay Heritage Center