Invasive Plants Information

What is an Invasive Plant?

In Connecticut, plants must demonstrate nine specific criteria to be listed on the state’s list of invasive and potentially invasive plants, which are defined in Sec.22a-381b of the CT General Statutes.  The nine criteria are:

1. The plant is nonindigenous to the state;
2. The plant is naturalized or has the potential to become naturalized or occurring without the aid and benefit of cultivation in an area where the plant is nonindigenous;
3. Under average conditions, the plant has the biological potential for rapid and widespread dispersion and establishment in the state or region within the state;
4. Under average conditions, the plant has the biological potential for excessive dispersion over habitats of varying sizes that are similar or dissimilar to the site of the plant's introduction into the state;
5. Under average conditions, the plant has the biological potential for existing in high numbers outside of habitats that are intensely managed;
6. The plant occurs widely in a region of the state or a particular habitat within the state;
7. The plant has numerous individuals within many populations;
8. The plant is able to out-compete other species in the same natural plant community;
9. The plant has the potential for rapid growth, high seed production and dissemination and establishment in natural plant communities.

The CT Invasive Plants List is prepared by the Connecticut Invasive Plants Council yearly. 

Why should we be concerned about invasive plants?

Invasive plants have the following qualities that make them nuisances and detrimental to the local ecosystem:

• Compete directly with native species for moisture, sunlight, nutrients and space.
• Alter the way animals, soils and water interact within native ecosystems.
• Spread quickly and easily to new areas.

How to identify an invasive plant

The following organizations provide information that can help you to identify an invasive plant:

• Connecticut Invasive Plant Working Group
• CT Department of Energy and Environmental Protection
• Connecticut Invasive Plants Council 
• Connecticut Agricultural Experiment Station .

Other documentation on invasive plant identification:

• Invasive Plants in Your Backyard from the Connecticut River Coastal Conservation District, Inc.
• Invasive Species Information from the Center of Invasive Species and Ecosystem Health at the University of Georgia.
• Invasive Plants Field and Reference Guide from the USDA.
• Invasive and Potentially Invasive Plant Early Detection List from the Connecticut Invasive Plant Working Group.

Management of invasive plants

Invasive plants, once established, are very hard to remove. Early detection is the best defense. Once established methods for removal from the Connecticut River Coastal Conservation District include:

• Mechanical Controls: These include digging, pulling, mowing, cutting and shading. This method is best for small areas of plant growth.
• Chemical Controls: These include the use of herbicides applied to foliage, cut stumps or basal bark.  This is best used on large areas of plant growth. This practice is recommended to be done by professionals as it does pose potential health and environmental risks.
• Biological Control: This includes the use of the plant’s natural enemies. However, there are only a few species that this has worked successfully on.

Other documentation on invasive plant management:

• The Connecticut Invasive Plant Working Group has an Invasive Plant Management Guide  along with information on herbicide control.
• Guidelines for Disposal of Terrestrial Invasive Plants
• Guidelines for Disposal of Aquatic Invasive Plants