Unwanted guests may be lurking around your property
It’s the “spooky” time of year. Halloween is right around the corner and haunted hay rides, horror movies and terrorizing theme park attractions are popular … all guaranteed to give you a good “scare”. I would like to add that there may be something that is equally scary right in your backyard or neighborhood. Something that may carry diseases to native plants, cause harm to wildlife species and upset the natural balance of our ecosystem. This scary situation affects our economy and can even change the chemistry of the soil. These alien creatures are not dreamed up by Stephen King … they are invasive plants.
The official U.S. government definition of an invasive species is “An alien species whose introduction does or is likely to cause economic or environmental harm to humans or human health” (www.invasivespeciesinfo.gov/laws/execorder. shtml). Invasive plants have characteristics that make them harmful to the environment. They have an excellent growth rate, produce a large number of seeds and germinate extremely well. Invasive plants spread rapidly and tend to out-compete native plants. Furthermore, removal is often costly and difficult. Invasive plants can be introduced to our local areas either intentionally or accidently. Some arrive by accident as their seeds “hitchhike” from animals or from humans. Sometimes seeds are found in soil and are unknowingly transported via vehicles though interstate travel. There are instances that plants were introduced to fight erosion many years ago, and they simply got out of control. Kudzu, for instance, is a well-known invasive vine species that can be seen along the highways in many parts of the state. It is a native of China and Japan and was introduced in the U.S. for erosion control and livestock feed. With a potential growth rate of 100 feet per growing season it easy overcomes native plants and trees and is now a costly problem. Some of today’s invasive plants were first introduced as ornamentals.
Oriental Bittersweet (Celastrus orbiculatus) is a vine species native to Asia that was introduced originally as an ornamental in the 1860’s. It is now listed as one of the top 10 worst invasive plants in the James River Park System and its damage is caused by providing too much shade and weight to small trees and native shrubs, thus weakening their root system. Another interesting fact is that Oriental Bittersweet is suspected to hybridize with American Bittersweet, thus throwing a wrench in our native plant ecosystem. Honeysuckle is another common
invasive, though we do have species native to Virginia. Coral Honeysuckle (Lonicera sempervirens) and Trumpet Creeper (Campsis radicans) are Virginia natives and are a popular nectar source for hummingbirds. Japanese Honeysuckle (Lonicera japonica) and Amur Honeysuckle (Lonicera maackii) are both extremely invasive and at one time were planted as landscape ornamentals and wildlife cover. The New York Botanical Garden was the first to import Amur Honeysuckle in 1898. What was once thought of as a helpful plant is now one that I would call a “scary species”.
Now, we all know good thriller novels that include an “evil twin” character that is the cause of much damage and despair. I would like to contend that the evil twin to our benevolent and beloved roses in our home gardens is the invasive Multiflora Rose (Rosa multiflora). Oh sure, it may have lovely white, fragrant flowers, and bears fruit of red to reddish brown “hips” lasting through the winter, but this Asian native plant is a looking to take over your landscape. It was imported to the U.S. in the 1860s as a rootstock for ornamental roses. As the Multiflora Rose has the qualities of providing a hedge, it was declared an erosion tool in the 1930’s by the U.S. Soil and Conservation Service. Years ago, it was even used in pastures as livestock fencing. However, despite the beauty of this rose, it is now another highly invasive species in our area. It is highly adaptive. It forms dense thickets and can overtake various habitats, including everything from open fields to wetlands.
The invasive Microstegium vimineum or Japanese Stiltgrass has an interesting history behind it. It is also a top 10 invasive plant species of the James River Park System. This grass is one of the most adaptable invasive plants and spreads virtually everywhere. It is extremely hardy and thrives in harsh conditions such as frequent mowing, heavy equipment use and even the natural flooding of wetlands. It has no real value to wildlife as a food source and easily overtakes native grasses. What is interesting about Japanese Stiltgrass is that it first came to our country in 1919 dried, and was a packaging material for porcelain. Just one Japanese Stiltgrass can produce as many as 1000 seeds and those seeds can stay in the soil for at least 3 years. I personally find that terrifying.
If you would like to learn more about Virginia’s invasive plant species, visit the Virginia Department of Conservation and Recreation website at www.dcr. virginia.gov and search invasive plants. You will find a complete listing as well as a classification of each species in accordance to their threat level. Additional information about invasive plant maintenance can be found at the Virginia Cooperative Extension website: https://ext.vt.edu . — Jennifer Mason is a Virginia Master Gardener with the Virginia Cooperative Extension Prince George County Office. Virginia Master Gardeners are volunteer educators who work within their communities to encourage and promote environmentally sound horticulture practices through sustainable landscape management education and training. Virginia Master Gardeners bring the resources of Virginia’s land-universities, Virginia Tech and Virginia State University to the people of the commonwealth.