By Gary L. Wade
University of Georgia
Volume XXXI |
This plant was first introduced to Americans at the 1876 Centennial Exposition in Philadelphia. It was promoted as a fragrant, flowering vine from Japan.
By the early 1900s, the U.S. Soil Conservation Service began using the vine to stabilize soil and control erosion. That's why you often see the plant along roadsides.
Meanwhile, the U.S. Department of Agriculture encouraged farmers to plant kudzu for cattle feed, since the forage value equaled that of alfalfa.
Then it began invading areas where it wasn't planted and engulfing everything in its path. Today the plant covers more than a million acres in the Southeast. By the mid-1900s, the once cherished vine became a noxious weed, and thoughts turned from how to grow it to how to get rid of it.
Kudzu can be managed and controlled. Other invaders pose a much more serious threat to our environment.
Chinese privet (Ligustrum sinense) is one of the most widespread invaders in the South. It creates thickets along rivers, smothering native vegetation. A single plant produces thousands of seeds that are spread by birds and water.
Chinese privet came from China in 1852 as a flowering shrub for the landscape. It wasn't a problem until the mid-1900s, when it escaped cultivation and invaded our woodlands.
Japanese honeysuckle (Lonicera japonica) was listed in the 1923 catalog of the William Prince Nursery in Long Island, N.Y. It was described as "one of the most prolific climbers in cultivation."
Unfortunately, it climbed far beyond where it was planted. It escaped cultivation and made itself at home in our woodlands. Today, it covers millions of acres throughout the Southeast. It's among the worst of the alien invaders.
The vine creeps along the ground, rooting along its stems and smothering other vegetation in its path. It climbs trees and wraps their canopies like a cocoon. Wild birds and animals eat the seeds, which pass through them unscathed to establish new colonies.
Another Asian invader is mimosa (Albizia julibrissin). Thomas Jefferson described it in his journal in 1805 as "one of the most beautiful of all the flowering trees" on his Monticello estate.
Introduced from Asia in 1745, Mimosa is a dazzling plant in spring. Its silky pink blooms look like powder puffs on top of the soft-textured foliage.
But the tree has a serious flaw: it produces an abundance of pea-like fruit pods, each containing five to 10 fertile seeds. The seeds remain viable for years. Wildlife and water carry them to new areas, where they sprout and form new colonies.
Young mimosa seedlings are shade-tolerant and soon crowd out native vegetation to form dense thickets. Today, Mimosa is among the most prolific and troublesome of the alien invaders.
While a few imported plants have caused havoc in our woodlands, not all exotic imports are invasive. In fact, only an estimated 1 percent of all the plants imported into the United States during the past two centuries have become invasive.
Unfortunately, that 1 percent has caused significant destruction of natural environments. They have given the other 99 percent a bad rap.
The Georgia Green Industry Association and the Georgia Exotic Pest Plant Council are working with the Georgia Department of Agriculture to:
- Manage invasive plant populations.
- Educate landowners, green industry professionals and gardeners about invasive plants.
- Develop a system for assessing new plants for invasive potential.
(Gary Wade is a Cooperative Extension horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.)
