Knotweed to Native

Invasive Plants Crowd Out Native Plants

Invasive Spotlight: Japanese Knotweed

Invasive Spotlight: Asiatic Bittersweet

  • Another ubiquitous and tenacious vine, Invasive (Asiatic) Bittersweet, is fast-growing, prolific, and aggressive. It quickly wraps itself tightly up and around neighboring shrubs and trees. This invasive is most likely in your own yard and girdling your healthy trees, both old and young alike. More established Oriental bittersweet has incredibly complex strong taproots (as well as endless networks) and a special heavy-duty wrench called The Uprooter may be required for removal.

SEE how to successfully tackle bittersweet in your own yard:


Why are Invasive Plants bad?

"Even hundreds of years after a non-native plant has been introduced to a geographic area, it supports only a fraction of the insects that it supports in its homeland." - Doug Tallamy

  • Invasive plants, such as Japanese knotweed, are quick to establish and form areas dominated by a single species, also known as monocultures.

  • Invasive plant species grow rapidly and spread quickly. These root systems often grow so densely that they smother the root systems of surrounding vegetation.

  • Invasive plants negatively impact biodiversity, reducing the quality and quantity of native plants and wildlife that depend on them for food and cover.

  • Invasive plants are long flowering, produce many seeds and fruits and they are aggressive competitors, free of the enemies that keep them in check in their natural range.

Invasive species can also be insects, birds, fish, snakes and other animals

As per the USDA, an invasive species is defined as a species that is: 1) non-native (or alien) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

When an animal, fish, insect or plant is taken out of its original ecosystem and introduced to a new one, whether by accident or on purpose, the results can be devastating. For a more thorough explanation, see Environmental Science Invasive Species: How They Affect the Environment, by Jacob Hill (February 23, 2015)

Find & Eradicate Invasive Plants in Your Own Yard

Domino Effect: Invasive Pests Can Harm Native Trees and Devastate Food Crops

A brief history of Invasive Management @ Allen Place by Karen Berger

Since 2017, Canton resident and Master Gardener, Karen Berger, has been working to eradicate the extremely invasive plant, Japanese Knotweed, growing in the median and on the slope along the trail at Allen Place. Found throughout Connecticut on roadsides and riverbanks, Japanese knotweed spreads aggressively and quickly dominates the landscape. One shoot of knotweed can grow half a foot each day and the tenacious invasive thrives in all soil conditions, particularly disturbed areas.

Joined by Cherry Brook Garden Club (CBGC) members, Allen Place neighbors, as well as UCONN Master Gardener interns (with hundreds of volunteer hours collectively behind them), the battle continues into 2020, as new shoots are already emerging. The long-term objective is to plant native grasses and perennials along Collinsville Pollen Trail to compete with the tenacious invasive plant.

photo by Katie Lukas


In the fall of 2016, Karen was inspired by a presentation by Abby Stokes and Petie Reed at the Connecticut Invasive Plant Working Group (CIPWG) symposium on the eradication of Japanese Knotweed in Pine Grove, Niantic.


With the support of Cherry Brook Garden Club and the UCONN Master Gardener program, interns and volunteers began the removal of a hedge of knotweed 375' long and 25' wide between Allen Place and Rails-to-Trails. The group cut, bagged and removed knotweed in three successive rounds each summer.


Karen applied for and received permits from Inland Wetlands & Watercourses Agency to hand-remove knotweed, and to cut and paint with herbicide the knotweed that descends the hill down to Rattlesnake Brook. (Please note this is a highly-targeted and extremely minimal application as opposed to indiscriminate spraying). She is eager to assess the efficacy of that treatment in Spring 2020. The original worked area was substantially diminished so that it could be maintained by mowing, while neighbors and other volunteers spent 150 hours filling 165 bags and clearing the entire 375' stand.


Continue maintenance phase of the original hedge area via cutting and mowing while planting native grasses and perennials to compete with the weeds and remaining knotweed. Karen and her team will continue to work with Emily Kyle, CZEO (Assistant Town Planner, Zoning Enforcement Officer and Inland Wetlands & Watercourses Agent) on knotweed eradication on the hillside.

Articles Citing Infestations of Knotweed:

Required Reading: Invasive Plants and Negative Impact on Local Ecosystems