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

tiny white flowers circling spiky central cone
cutleaf teasel
Photo by
Zeynel Cebeci via Wiki CC, taken in Turkey
Frangula alnus spent flowers
glossy buckthorn
Photo by
Steven Daniel (taken in Livingston Co. NY)
yellow flag iris
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
lesser celandine
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
Japanese knotweed
Level 1
Photo by
Leslie J. Mehrhoff, University of Conn., Bugwood.org
giant knotweed
Level 1
Photo by
Robert Vidéki, Doronicum Kft., 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)
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
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, Univ. of GA, Bugwood.org
light lime green leaves, yellow flowers
moneywort
Level 2
Photo by
Stefano via flickr CC
large stand purple loosestrife by pond
purple loosestrife
Level 2
Photo by
Liz West via Flickr CC
Redoute drawing of Myosotis scorpioides
water forget-me-not
Level 2
Photo by
PJ Redoute via Swallowtail Seeds/Flickr
invasive Myriophyllum spicatum
Eurasian water-milfoil
Level 2
Photo by
Rob Routledge, Sault College, Bugwood.org (taken MI)
reed canary grass
reed canary grass
Level 2
Photo by
M. Costea and K. Stevens, source: CUPIC
curly leaves of pondweed
curly pondweed
Level 2
Sakhalin knotweed
Level 2
Photo by
Tom Heutte, USDA Forest Service, Bugwood.org
compound leaves, drooping raceme of white flowers
black locust
Level 2
Photo by
Steven Daniel
dark blue-black berries with "bloom"
European dewberry
Level 2
Photo by
Nicholas Turland via flickr CC
small dark purple flowers with yellow centers
bittersweet nightshade
Level 2
Photo by
Steven Daniel
parsley like foliage & flower
Japanese hedge parsley
Level 2
Photo by
Qwert1234 via Wiki CC
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