Cattail

“Invasive plants are species intentionally or accidentally introduced by human activity into a region in which they did not evolve and cause harm to natural resources, economic activity or humans. Invasive plants proliferate and displace native plant species, reduce wildlife habitat and alter natural processes. They also impose serious costs on our economy, which depends on benefits provided by nature. Economists have estimated that all invasive species - plants, animals and diseases - cause $120 billion in losses each year” (Pimentel, et al., 2005). Examples of these costs include degradation of vast areas of western rangelands, clogging of important waterways and increased effort to maintaining open power line rights-of-way.

In 1970, when I entered the wonderful world of Arboriculture, I had no idea about the impact of invasives on our ecosystems and the effects they have on our everyday lives. At the time, the main invasive I had experience with was the Elm bark beetle, the vector for Dutch Elm disease which was mainly responsible for wiping out the American Elm tree. 

The other was the Cattail (Typha latifoilia). As children we thought nothing of their invasiveness but only how cool they looked growing in the swamps and being used by birds for landing props. We also used them for torches during camp outs. Cattails grow tall, up to 10 feet, shading out native plants while producing massive amounts of leaf litter which acts as a mulch, further smothering and choking out native plants. Although considered an invasive, Cattail actually was a very useful resource throughout history. The cotton from Cattail was used as filling for pillows, chair cushions and even life jackets. Native Americans used the cotton from Cattails to line their moccasins and papoose boards.

Bristle Basketgrass

The Commonwealth has many invasive species and according to the Virginia Cooperative Extension, it costs about one billion annually for control efforts. This includes, but is not limited to cattails, kudzu, oriental bittersweet, and a relatively new one (Oplismenus undulatifolius) also known as Wavyleaf Grass, which can completely take over the understory areas of forests by growing dense carpets that choke out seedlings and other ground layer species. (Virginia Department of Conservation and Recreation)

Kudzu

Another highly invasive plant in the Commonwealth, is Kudzu (Pueraria montana var. lobata). Who would have thought that something so beautiful would be so destructive? Kudzu was brought to the US by the Japanese for the Centennial Exposition in Philadelphia in 1876. It captured the interests of many American gardeners because of the wonderful smelling flowers and large leaves. Its use was encouraged for erosion control and fodder for cattle. Growing as much as a foot per day and up to 60 feet per year, it quickly encapsulates anything in its path. Forests can be decimated by the vigorous growth as the vines shade out the understory plants and even the trees themselves. As with many introduced invasive species, its natural predators did not come with it, which allowed it to thrive in its new environment.

After eighteen years of research, Dr. James H. Miller of the U.S. Forest Service in Auburn, Alabama has found that one herbicide actually makes Kudzu grow better and several have no effect. He recommends repeated applications of herbicide for at least four years, while some may require ten years of repeated applications. While herbicides do work, conclusive eradication can be achieved by the use of goats. They can keep the kudzu contained and eventually will deplete the food storage capability of the root system resulting in successful control.

Oriental Bittersweet

Others who choose to make lemonade out of lemons use the resource to their advantage. Kudzu vines can be used to make baskets, to jelly from the blossoms, paper from the leaf fiber, and many other food dishes from the leaves.  Over its history, people have gotten creative with the vine, but one thing is for sure; it has proven to be a love it or hate it plant.

An invasive that often appears in wreaths is Oriental Bittersweet (Celastrus orbiculatus), not to be confused with Native bittersweet (Celastrus scandens, L). Oriental has yellow capsules around red fruit while American has orange capsules around red fruit. Spread by disposal of ornamental wreaths and birds, it grows like kudzu, encapsulating, girdling and shading out native plants and understory trees. The growth habit of Oriental Bittersweet is massive with vines up to 60 feet that are capable of pulling down trees and plants. Oriental Bittersweet can be controlled with frequent mowing along with herbicide treatment.

Giant Salvinia

Although there are a number of other invasive plants that I could mention, a final species I would like to reference is Giant Salvinia (Salvinia molesta). Native to northern Argentina and southeastern Brazil, Giant Salvinia is a very vigorous aquatic plant commonly found in lakes and ponds. A single plant can multiply to cover 40 square miles of surface area in only three months – or the length of a typical Mid Atlantic summer - causing a total elimination of oxygen in the water which then kills off any life below the surface. It was discovered in a small pond in Shenandoah County Virginia in 2004 and was successfully eradicated, but bares mention so we remain vigilant in discovering a reoccurrence. To give you an idea of the enormous impact it can have on the environment and the fiscal budget, Louisiana spends nearly 9 million dollars a year spraying aquatic nuisance vegetation with three quarters of that used for Salvinia control. 

The first step in controlling an invasive species is awareness and vigilance in control methodology. If you encounter any of the plants mentioned above, and prior to attempting to eradicate the invasives on your own, you may first want to consider contacting your local Virginia Cooperative Extension office.  

 

Kevin E Beal, Arborist/Landscape Supervisor Senior

Facilities Management, University of Virginia

Cell-434-531-7214;  Office-434-924-8904

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Ex-Officio seat Trees Virginia

References

Virginia Department of Conservation and Recreation (2017) Virginia Invasive Plants Early Detection Species.  

Pimentel, D., Zuniga, R., & Morrison, D. (2005). Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics, 52(3), 273 - 288. Retrieved from: https://doi.org/10.1016/j.ecolecon.2004.10.002 

Did You Know:

  • A birdhouse hung on a young tree branch, does not move up the tree as the tree grows.

  • A mature tree removes almost 70 times more pollution than a newly planted tree.

  • Most trees do not have a tap root.

  • Well-maintained trees and shrubs can increase property value by up to 14%.

  • In one day, one large tree can lift up to 100 gallons of water out of the ground and discharge it into the air.

  • Trees are the largest living organisms on earth: some coastal redwoods are more than 360 feet tall.

  • Trees properly placed around buildings can reduce air conditioning needs by 30 percent and save 20-50 percent in heating energy.

  • Trees are some of the oldest living organisms on earth: some bristle-cone pines are thought to be more than 5000 years old.

  • One large tree can provide a supply of oxygen for two people.

  • Every state has an official State Tree. Virginia adopted the flowering dogwood Cornaceae Cornus florida as the State Tree on February 24, 1956.  The dogwood is well distributed throughout the...

  • Most tree roots are in the top 12 inches of soil.

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