Minutes September 17 — Invasives


Gardeners Exchange Group Meeting 17 September 2016
Location: Home of Julie and Wayne Neely
Topic: Invasives and You
Submitted by Julie Neely, GEG Secretary

Our sixth and last meeting this year was held at the historic home and grounds (circa 1821) of the Neely family: Julie, Wayne, and Matty. Louise Finch, who has been a Master Gardener for ten years and is the coordinator for the Speakers Bureau of the Berkeley/Jefferson Extension Master Gardener Association gave a practical and informative lecture about local area invasive plants. Photos of the invasives we discussed were used throughout the lecture which proved to be very helpful for identification purposes. Managed by the National Agricultural Library, the National Invasive Species Information Center (NISIC) website is the official reference gateway to information, programs, organizations, and services about invasive species. Download the References for Invasives handout from the meeting.

We started the lecture with a few definitions.

  • An invasive plant is non-native (alien) to the ecosystem under consideration, whose introduction will cause economic, environmental, or domestic harm to human health.
  • Human action is the primary means of introducing invasive species.
  • An invasive is a plant introduced into an environment in which it did not evolve, therefore it has no natural checks and balances to inhibit reproduction and spread. The invasive will outcompete the naturally present native species and alter the ecosystem function.
  • An invasive plant is out of balance with the surrounding community as described by Douglas Tallamy in his book Bringing Nature Home.
  • The key traits that make a non-native plant an invasive plant are that it can grow extremely rapidly, produce large number of seeds, may propagate vegetatively, may produce inhibiting chemicals, and may adapt to many environments.
  • Noxious weeds are plants determined to be injurious to public health, crops, livestock, agricultural land or other property. See the Federal Noxious Weed Act of 1975.

Why should we be concerned about invasive plants?

Why not just let nature sort things out? Invasives cause dramatic changes to soil moisture levels, soil structure, and available sunlight by overtaking and eradicating native species of vegetation. They decrease the number and diversity of insects and soil microorganisms. They change the availability of habitat and food sources for animals reliant on the native vegetation, displacing these native species. Louise explained that invasive species first of all are not natural; they are introduced by people and do not belong naturally in the location they are now found. When we disturb the soil and remove natural vegetation, thereby changing the soil moisture and sunlight levels, we give invasive plants and seeds a golden opportunity to “invade” the newly available space. Some invasives were deliberately introduced from foreign countries, usually Asia, as ornamental plants for gardens or to provide structure and boundary fencing, as in the case of the multiflora rose. Some invasives arrived in the U.S. accidentally included in or used as packaging material, such as japanese stilt grass, used to cushion porcelain and china goods.

How can we manage invasive plants?

Early Detection, Rapid Removal (EDDR): It is important to be educated about invasive plants. The critical first stage is recognizing and immediately hand pulling small infestations. Once you have a larger infestation, frequent cuttings and mowing may eventually eliminate the plant. Louise stated that 7-10 years of mowing Japanese Stiltgrass before it sets seeds usually eliminated that plant–where mowing is possible. Shrubs can be dug up, and larger shrubs and trees may have to be cut down and the stumps treated with herbicide. Louise clarified that it is required by law for anyone using herbicides to follow the directions for use and disposal on the manufacturers label. Restricted Use Pesticides require a private applicator license available at the Cooperative Extension office.

West Virginia State Listed Noxious Weeds

Noxious weeds: Autumn Olive also known as Russian Olive, Curled Thistle, Kudzu (despite its being delicious), Johnson Grass, Marijuana, Multiflora Rose, Musk Thistle, Opium Poppy, Plumeless Thistle

Status of Invasive Plants in West Virginia, Top Ten Most Abundant (by number of reports): 1-Multiflora Rose, 2-Tree of Heaven, 3-Japanese Knotweed, 4-Japanese Honeysuckle, 5-Autumn Olive, 6-Common Teasel, 7-Japanese Stiltgrass, 8-Ground Ivy also known as Creeping Charlie, 9-Garlic Mustard, 10-Poison Hemlock

Also mentioned as local examples of invasives worth noting and removing: Mile-a-Minute Vine, various thistles (Canadian, Spiny Plumeless), Common Teasel, Japanese Barberry