What a plant needs to do to be a Connecticut invasive

What a gardener refers to as invasive might really be no more than a garden thug – a plant that doesn’t understand how to play nicely with its neighbors and aggressively crowds other plants. Garden thugs may be a pain in the root to neighboring plants, or a pain in the gardener’s back – or more southerly bit of human anatomy – but a plant thug may not pass the nine point test required to be named a Connecticut invasive.

To date, 97 different plant species have been added to the Connecticut Invasive Plant list. Each meets the following criteria – all nine of them. The plant

  • is nonindigenous to Connecticut – it was not here before European colonization;
  • is naturalized or has the potential to become naturalized – it’s happy here;
  • has the biological potential for rapid and widespread dispersion and establishment – it can spread easily;
  • has the biological potential for excessive dispersion – it can spread excessively;
  • has the biological potential to exist in high numbers outside of intensely managed habitats – for example, in woods, fields, wetlands;
  • it can be found in wide regions or in particular habitats within Connecticut;
  • it has grown into large stands;
  • it can out-compete other plants;
  • and, it has the potential for rapid growth, high seed production and dissemination, and establishment in natural communities.

This photo of Japanese barberry overtaking a forest floor is a good example of a Connecticut invasive.


Japanese barberry, garlic mustard, Oriental bittersweet, Russian and Autumn olive, Winged euonymus, a.k.a. burning bush, ground ivy, many honeysuckles, moneywort, Japanese knotweed, multiflora rose and sheep sorrel are some of the invasive plants common to Connecticut gardens, as is mugwort, the most recent addition to the Connecticut Invasive Plant list. (The October 2012 update lists mugwort. As of the date of this post, the October 2011 online version, does not.) Many of these plants are so invasive they are found in every Connecticut county.

Of the 97 plant species considered invasive in Connecticut, 80 are illegal to import, move (unless for research, control, or education purposes), sell, purchase, transplant, cultivate, or distribute, according to information provided to attendees at the Invasive Plant Symposium held October 25, 2012 at the University of Connecticut. Notice I said just 80 of Connecticut’s invasives are prohibited. This means 17 can still be sold and purchased, planted and distributed in spite of their invasive label.

Becoming familiar with the Connecticut Invasive Plant list is one way for Connecticut gardeners to garden thoughtfully. It’s much better to identify a plant as invasive before giving it a chance to do its invasive thing in your garden or on your property. It’s also valuable to know how to recognize invasive plants when they first show themselves. Eradication is so much easier when plants are young.

OLYMPUS DIGITAL CAMERA Gardeners can learn to identify many invasive plants by clicking the plant names listed at Invasipedia! Plants are listed there by their botanical names so be sure to have a nearby reference copy of the invasive plant list, which refers to plants by their botanical and common names. You can also just Google the botanical name of a plant to quickly see descriptions and photos.

There are good identification guides, some with color photos, as well as control and disposal information available through the Connecticut Invasive Plant Working Group website. After all, once you identify an invasive plant on your property it’s important to know how to remove it or control its spread.

I have my list of ‘favorite’ invasives  – Japanese barberry; Oriental bittersweet; Autumn olive which produces 80 pounds of bird-favored fruit per year which birds then ‘distribute’ in excreted seed form; mugwort; multiflora rose; plus my two more recent faves, Japanese stilt grass and sheep sorrel. A good portion of my gardening hours are spent controlling this group. I strive to get to know my problematic plants when they are young, so one or two small troublemakers don’t become enormous pains to parts of my anatomy. But control also requires vigilance – you have to keep continuous watch for the invasives common to your property. They love to visit again and again and again.

Digiprove sealCopyright secured by Digiprove © 2012 Joene Hendry

2 comments for “What a plant needs to do to be a Connecticut invasive

  1. October 28, 2012 at 10:25 am

    I liked Rick Darke’s definition of an invasive plant — “a hyper-adaptive native from somewhere else.” The common area behind my yard is a mini laboratory of all the plants on the CT list. They are all battling for control of what I want to be a grassy wildflower meadow!

    • October 28, 2012 at 6:57 pm

      Keep up the good fight, Laurrie. With your oversight the invasives will remain in control so the natives can thrive.

Leave a Reply

%d bloggers like this: