Knotweed to Native
Invasive Plants Crowd Out Native Plants
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
- The invasive plant, Garlic Mustard, is toxic to some butterflies. Researchers have found that it disrupts a healthy relationship between hardwood tree seedlings and soil fungi, with results that can be disastrous for a forest. Further info can be found in Recommendations for Garlic Mustard Management by Dr. Kristina Stinson et. al, UMass Amherst, 2018.
- One ubiquitous and tenacious vine, Invasive Oriental 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.
- For more info on weed removal without chemicals, see Beyond Pesticides: Least-toxic Control of Weeds
- Invasive Plants In Your Backyard! A Guide to Their Identification and Control - Connecticut River Coastal Conservation District, Inc. with support/input from Connecticut Invasive Plant Working Group (September 2016)
Domino Effect: Invasive Pests Can Harm Native Trees and Devastate Food Crops
- The Spotted Lanternfly (Lycorma delicatula) is native to Asia and feeds primarily on one type of tree: Tree of Heaven, which is ALSO an invasive species in the U.S. The Spotted Lanternfly has been reported in Connecticut and is on the Connecticut Agricultural Experiment Station watch list - it could potentially harm half of our forest trees and devastate the agricultural industry in Connecticut. Here is how you can help:
- REPORT The Spotted Lanternfly to CAES (The Connecticut Agricultural Experiment Station)
- REPORT Tree of Heaven in groups of 10 or more (The Connecticut Agricultural Experiment Station)
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:
- Oh, No, Not Knotweed! It grows rapidly. It’s nearly impossible to kill. It’s terrorized England. And now it’s all over my American backyard. - SLATE article by Henry Grabar (5/8/2019)
- Japanese Knotweed – Invasive in Connecticut - CONNECTICUT GARDENER MAGAZINE (9/1/2018)
- Japanese Knotweed: The Invasive Plant That Eats the Value of Your Home - NEWSWEEK MAGAZINE article by Christopher Middleton (07/05/2014)
Required Reading: Invasive Plants and Ecosystems
by Jerry Adler - SMITHSONIAN MAGAZINE (April 2020)