Control Information

Invasive Plant Management Guide

Invasive plants present an increasing threat to natural communities throughout Connecticut and the United States. These non-native invaders are often referred to as a form of "biological pollution" that is sweeping through natural and minimally managed landscapes. Controlling invasive plant populations is important to reduce negative impacts on these ecosystems. Early detection and action is vital in any management plan. This guide is intended to assist with identification of invasive plants and provide information on controlling these problem plants. We have included both non-chemical means of control as well as information on proper use of herbicides where chemical controls are needed. The choice of control measure depends on the size and nature of the infestation. If dealt with early enough, invasive plant problems can often be eliminated by non-chemical methods. However, a herbicide-based approach may be required to control an infestation that has become well established or widespread.

This management guide will be updated periodically to include additional invasive plants and more information about management of plants already included in this version.

The guide is available at

(updated 2018)

Invasive Plants Listed in Control Guide

Common Name Scientific Name Related Links Image
Herbaceous Plants
Garlic Mustard Alliaria petiolata  NicoleGarlicMustard
Common Reed, Phragmites Phragmites australis  NicolePhrag
Purple Loosestrife Lythrum salicaria  DonnaPurpleLoose
Spotted Knapweed Centaurea stoebe  MehrhoffSpottedKnap
Japanese Knotweed (Not Bamboo) Polygonum cuspidatum  DonnaJapKnot
Woody Plants (Trees, Shrubs, Vines)
Japanese Honeysuckle Lonicera japonica  MehrhoffJapHoneysuckle
Morrow's Honeysuckle Lonicera morrowii  DonnaMorrowHoneysuckle
Multiflora Rose Rosa multiflora  RobRoutledgeSaultCollegeBugwood
Japanese Barberry Berberis thunbergii  MehrhoffJapBarb
Common (European) Buckthorn, Smooth (Glossy) Buckthorn Rhamnus cathartica, Frangula alnus (R. frangula)  MehrhoffCommonBuck
Autumn Olive Elaeagnus umbellata  MehrhoffAutumnOlive
Tree-of-heaven Ailanthus altissima  ChuckBargeronUofGABugwood
Black Locust Robinia pseudoacacia  MehrhoffBlackLocust
Norway Maple Acer platanoides  NicoleNorway
Other Plants
Black Swallow-wort Cynanchum louiseae  MehrhoffBlackSwallowwort
Winged Euonymus Euonymus alatus  NicoleWingedEuonymus
Poison Ivy (Problem native; not “invasive” per definition of CT Invasive Plant criteria) Toxicodendron radicans  NicolePI