Invasive Species of Tompkins County, New York

About one-third of the plant species in New York State are non-native but only a small percentage of these are considered "invasives." Learning to recognize these aliens is an important first step in controlling them. Left alone, they can spread and eventually replace our native flora due to different advantages they may have. Some, like the honeysuckles (Lonicera spp.), begin leafing out earlier in the spring than our natives, thereby depriving the native species of the sunlight they need. Many find that the local environment lacks the animals and plants that kept them in check in their native country. Several species produce toxins in the soil that kill the growth of neighboring plants. Since each has its own exploitation strategy, it is good to understand its success mechanism, especially when it comes to removing them.

As is the case with many problematic situations, prevention is unarguably the first line of defense. In many cases we introduce these aliens unknowingly as hidden seeds on our food or wood products. A number of our invasive plants have characteristics that encourage their cultivation: many are attractive, grow fast, and need little attention. We even spread them unintentionally on our hiking boots and car tires, as many invasives start their journeys along roadsides.

Prevention makes even more sense when one considers the options available for removing the invaders. Simply pulling up rhizomatous plants will often help to propagate them. Applying herbicides is often ineffective, too costly, or dangerous to the environment. Mowing is effective in many cases but it must be repeated several times per season and then repeated for several years before the energy is depleted in the root system. The best advice here is to understand why the particular invader is so successful and minimize or eliminate that advantage.

The following is a list of the common invasive plants in the Finger Lakes area with links to sites where you can find more information. (For more compact, printable list click here.) The levels indicate relative problem in the Cayuga Lake basin as determined by Cornell field botanist F. Robert Wesley. (Level 1 is worst, most concern; Level 2 is moderately bad; Level 3 is less problematic but still of concern.) Please contact us if you have any questions on this subject.

Invasive Plants

Norway maple
Level 1
ailanthus
Level 1
Photo by
Paul Wray, Iowa State Univ., Bugwood.org
garlic mustard
Level 1
mugwort
Level 1
Photo by
Ohio State Weed Lab, OH State Univ., Bugwood.org
Japanese Barberry
Level 1
Asian bittersweet
Level 1
Photo by
James R. Allison, GA Dept of Nat'l Res., Bugwood.org
creeping thistle
Level 1
Photo by
C Evans, IL Wildlife Action Plan, Bugwood.org
crownvetch
Level 1
Photo by
D Tenaglia, Missouriplants, Bugwood.org
pale swallowwort
Level 1
Photo by
JM Randall, The Nature Conservancy, Bugwood.org
autumn olive
Level 1
Photo by
PA DNR - Forestry Archive, Bugwood.org
giant knotweed
Level 1
Photo by
Robert Vid├ęki, Doronicum Kft., Bugwood.org
Japanese knotweed
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
hydrilla
Level 1
Photo by
Cleveland Metroparks, Bugwood.org
Amur River privet
Level 1
Photo by
Nancy Loewenstein, Auburn University, Bugwood.org
Maack's honeysuckle
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
honeysuckle
Level 1
Photo by
Leslie J. Mehrhoff, Bugwood.org
Tartarian honeysuckle
Level 1
Photo by
Patrick Breen, Oregon State University, Bugwood.org
stilt-grass
Level 1
Photo by
Chris Evans, Illinois Wildlife Action Plan, Bugwood.org
mile-a-minute vine
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
phragmites
Level 1
Photo by
James H. Miller
lesser celandine
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
buckthorn
Level 1
Photo by
Jan Samanek, Bugwood.org
alder buckthorn
Level 1
Photo by
Rob Routledge, Sault College, Bugwood.org
multiflora rose
Level 1
Photo by
Rob Routledge, Sault College, Bugwood.org
water-chestnut
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
hedge maple
Level 2
Photo by
Zelimir Borzan, University of Zagreb, Bugwood.org
Asian maple
Level 2
Photo by
Rob Routledge, Sault College, Bugwood.org
bishops weed
Level 2
wild onion
Level 2
Photo by
Ohio State Weed Lab, Ohio St. Univ., Bugwood.org
European black alder
Level 2
Photo by
Zelimir Borzan, University of Zagreb, Bugwood.org
European barberry
Level 2
Photo by
Leslie J. Mehrhoff, Univ. Connecticut, Bugwood.org
fanwort
Level 2
Photo by
Leslie J. Mehrhoff, Univ of Conn., Bugwood.org
hairy cress
Level 2
Photo by
Leslie J. Mehrhoff, Univ of Conn., Bugwood.org
brown knapweed
Level 2
Photo by
Rob Routledge, Sault College, Bugwood.org
spotted knapweed
Level 2
Photo by
Matt Lavin (Flickr, Wikimedia)
Spotted Knapweed
Level 2
Greater Celandine
Level 2
black swallowwort
Level 2
Photo by
Leslie J. Mehrhoff, Univ. Connecticut, Bugwood.org
burning bush
Level 2
Photo by
James H. Miller, USDA Forest Service, Bugwood.org
leafy spurge
Level 2
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
Sakhalin knotweed
Level 2
Photo by
Tom Heutte, USDA Forest Service, Bugwood.org
white bedstraw
Level 2
Photo by
Ohio State Weed Lab Archive, OSU, Bugwood.org
English ivy
Level 2
Photo by
Chuck Bargeron, University of Georgia, Bugwood.org
daylily
Level 2
Photo by
Dan Tenaglia, Bugwood.org
giant hogweed
Level 2
Photo by
Terry English, Bugwood.org
frog-bit
Level 2
Photo by
Leslie J. Mehrhoff, UConn., Bugwood.org
California privet
Level 2
Photo by
Leslie J. Mehrhoff, UConn, Bugwood.org
common privet
Level 2
Photo by
Leslie J. Mehrhoff, UConn, Bugwood.org
Japanese honeysuckle
Level 2
Photo by
Chuck Bargeron, Uni. of GA, Bugwood.org
moneywort
Level 2
purple loosestrife
Level 2
forget-me-not
Level 2
Eurasian water-milfoil
Level 2
reed canary grass
Level 2
curly pondweed
Level 2
black locust
Level 2
European dewberry
Level 2
bittersweet nightshade
Level 2
Japanese hedge parsley
Level 2
European cranberry viburnum
Level 2
periwinkle
Level 2
dame's rocket
Level 3
Photo by
David Cappaert, MSU, Bugwood.org
slender false brome
Level 4 - newly introduced or troublesome but not on Wesley list yet
Photo by
The Nature Conservancy Archive, Bugwood.org