Invasive Plants in Southwest Virginia Natural Areas

As a trainee with the Holston Rivers Chapter of the Virginia Master Naturalist Program based in Washington County, Virginia, I chose to develop a blog on invasive plants in southwest Virginia natural areas as a class project. The pictures and information, here, are a combination of research with the Department of Forestry, Virginia Tech documentation, various other weed ID guides, and field notes taken on containment trips with the Appalachian Trail Club.

From the Natural Heritage site:
http://www.dcr.virginia.gov/natural_heritage/invspinfo.shtml

"Invasive alien plants...become agricultural pests, infest lawns as weeds, displace native plant species, reduce wildlife habitat, and alter ecosystem processes. Across the country and around the world, invasive alien plants and animals have become one of the most serious threats to native species, natural communities, and ecosystem processes. They also exact a costly toll from human economies that depend on resources and services provided by healthy ecosystems. Examples include destruction of vast areas of western rangelands, clogging of important waterways, and increased costs in maintaining open powerline rights-of-way.

The Virginia Department of Conservation's Division of Natural Heritage and the Virginia Native Plant Society have identified 115 invasive alien plant species that threaten or potentially threaten natural areas, parks, and other protected lands in Virginia."

Autumn Olive (Elaeagnus umbelata)

Date: March 7, 2009

Location: The Appalachian Trail, approx. 9 miles from Damascus near Route 58 just above Bear Tree Gap road.

We walked on a spur about 1/5 mile south from Route 58 to the intersection of the Appalachian Trail to cut back Autumn Olives growing back in this open area after being cut back last year. Many were sprouts from the trunk stubs but we also found several large ones that were missed on previous trips.

Orginally brought to the states as a landscape ornamental, Autumn Olive has been planted in recent years to remediate strip mine sites. The berries are popular as a wildlife food.

March 18, 2009
Location: Appalachian Trail SR679 near Sugar Grove, VA.

This shows my grandson, Grayson Blackburn, in the middle of a stand of Autumn Olive in an open meadow at this Appalachian Trail location. We used loppers for small ones and bowsaws for the larger ones.

Coltsfoot (Tussilago)

A perennial herbaceous plant that spreads by seeds and rhizomes, Tussilago is often found in colonies of dozens of plants. The flowers, which superficially resemble dandelions, appear in early spring before dandelions appear. The leaves, which resemble a colt's foot in cross section, do not appear usually until after the seeds are set. Thus, the flowers appear on stems with no apparent leaves, and the later appearing leaves then wither and die during the season without seeming to set flowers. The plant is typically between 10-30 cm in height.

Garlic Mustard (Alliaria petiolata)

Cultivated for food and medicinal use, it is a cool season plant.

Once introduced to an area, garlic mustard outcompetes native plants by aggressively monopolizing light, moisture, nutrients, soil and space. It is especially prevalent along the New River Trail from Pulaski to Galax, Virginia.

Japanese Stilt Grass (Microstegium vimanium)

Japanese stilt grass was first introduced into the United States in Tennessee around 1919 and likely escaped as a result of its use as a packing material for porcelain.

It spreads opportunistically following disturbance to form dense patches, displacing native wetland and forest vegetation as the patch expands. Japanese stilt grass appears to be associated with moist, acidic to neutral soils that are high in nitrogen.

Stiltgrass spreads to form extensive patches, displacing native species that are not able to compete with it. Where white-tail deer are over-abundant, they may facilitate its invasion by feeding on native plant species and avoiding stiltgrass. Japanese stiltgrass may impact other plants by changing soil chemistry and shading other plants. When a tornado came through Lee County, Virginia, in 2007 and knocked down large areas of trees on Powell Mountain, Stiltgrass took over some areas even though these areas were reseeded with other grasses.

Because it is similar in appearance to several native grasses, it is important to know how to recognize and differentiate stilt grass from look-alikes. The shiny midrib and asymmetrical leaves help to distinguish stilt grass. Small Stiltgrass patches can be controlled by hand pulling as the roots come out of the ground easily.

Purple Loosestrife (Lythrum salicaria L.)

Brought here as an ornamental. Although colorful, this plant prevents many desirable native wetland plants, such as cattails, from becoming established.

Some good resources for information on invasive plants:

http://www.dcr.virginia.gov/natural_heritage/invspfactsheets.shtml
http://dnr.state.il.us/Stewardship/
http://www.hort.purdue/edu/
http://www.invasive.org/weedus/
http://www.ppws.vt.edu/weedindex.htm
http://www.usna.usda.gov/Gardens/invasives.html
http://www.nj.nrcs.usda.gov/documents/Mistaken_Identity.pdf