This is a re-post from October 2012, but the information is still valid and important.
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.
- 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.