Popcorn trees

Popcorn trees are far from a treat

Landowners urged to eradicate this invasive tree

By Lenela Glass-Godwin

Our founding father Benjamin Franklin was known for his wisdom and sound advice during his lifetime, and he is still admired today for the legacy of common sense suggestions he left us. But even the architects of great countries make mistakes.

Mr. Franklin made a big one when he introduced the Chinese tallow tree (Sapium sebifera or Triadica sebifera) to the eastern United States during the colonial period. His error in judgment is one from which the South is likely to suffer for a long time.

Chinese tallow tree, also known as popcorn tree or Florida “aspen,” is native to eastern Asia. Unfortunately, plants like tallow trees, kudzu, privet, mimosa, Japanese honeysuckle, chinaberries, and a host of other Asian plants that may not pose problems in their native countries have created colossal invasive nightmares in the southern U.S.

One of the biggest headaches facing land managers now on the Atlantic and Gulf coastal plains is the tallow tree. A deciduous tree with bright, waxy green heart-shaped leaves that turn glowing red in autumn, tallow trees may grow 40 to 50 feet in height. In the spring the trees produce long, light-green inflorescences that are easily seen even from a distance. In September and October dark brown, three-valved fruits mature, producing the characteristic “popcorn” seeds that are spread far and wide by both water and birds.

For many years tallow trees were planted by property owners as ornamentals for the yard. Many people thought that they were

just planting an exotic that would provide shade and pretty fall color. But the private landowner who continues to allow a tallow tree to grow on his property does a great disservice to his neighbors as the trees quickly invade adjoining properties and are extremely difficult to control.

According to Dr. Nancy Loewenstein of the Alabama Cooperative Extension Service, a mature tree can produce more than 100,000 seeds per year and the trees also propagate by means of “runners” or “suckers.” The leaves and sap of these trees are toxic to humans and cattle and can cause serious illness if ingested. Most states have now declared tallow trees a noxious weed.

The Chinese tallow tree is spreading like an aggressive cancer throughout Alabama, and is now a problem in all of the south and central parts of the state. The website www.eddmaps.org provides an excellent representation of the current distribution of tallow trees in the South. The tree has taken over huge areas along the banks of the Coosa, Alabama, and Tallapoosa Rivers and is steadily invading many wetlands. It rapidly overtakes unmanaged pasture areas and abandoned farms, and because certain bird species disperse the abundant seeds in their droppings, it is often seen growing along fence lines where birds perch. The fence lines and pastures along Interstate 65 south of Montgomery close to the Hyundai plant are prime examples of unchecked tallow tree growth in upland areas.

Concerned land managers throughout the southeastern U.S. who are fighting the spread of invasive pest plant species are encouraging property owners to eradicate the Chinese tallow tree from their yards and land holdings. According to Dr. James Miller of the U.S. Forest Service, forest landowners can take a number of steps to control or eradicate this pest species. Small specimens (diameter of less than 6 inches) of tallow tree should be pulled up as soon as they are observed, and foliar applications of herbicides may also be used to kill young trees.

For larger trees with a diameter of more than 6 inches, the trees should be cut with a chainsaw as close to ground level as possible. After that, herbicide applications to the cut stumps or basal bark are essential. A 15-20% application of the herbicide triclopyr (found in formulations such as Ortho Brush-B-Gon and Bayer Advanced Brush Killer) mixed with oil should be sprayed on the root collar area, sides of the stumps, and outer portion of all cut surfaces until thoroughly wet. The herbicides Garlon 3A and 4, Arsenal AC, and Clearcast are also effective. Herbicide treatments are best done during early to mid-growing season before the trees have a chance to set seed. For specific application information, consult A Management Guide for Invasive Plants in Southern Forests, General Technical Report SRS-131, written by James Miller, Steven Manning, and Stephen Enloe and published by the U.S. Forest Service.

For more information on Chinese tallow tree invasion and eradication advice, please contact your county office of the Alabama Cooperative Extension Service, or check out the Alabama Invasive Plant Council website at www.se-eppc.org/alabama/