Editor’s note: Alicia Campanella is filling in this month for Eric H. Hoyer.
Chinese tallow-tree, Sapium sebiferum, native to Eastern Asia, was introduced in the U.S. in the 1800s. Like most exotic introductions, this plant was thought to be beautiful, useful and economically beneficial — especially because of its seeds and oils. The seeds are rich in fatty acids and amino acids, and when processed, yield a flour rich in B vitamins. The kernels are rich in iodine, and the oil is used as a drying and preserving agent. Adding to this list of useful traits are several documented uses in Chinese medicine and the tree’s attractive foliage, so it is easy to see why the tree was so appealing.
Recognition of this plant as an aggressive invader did not occur in time to prevent it from becoming a problem, replacing thousands of acres of native habitat, leaving thick, biologically impoverished monocultures in its wake. Today, it is found in every region of Florida, excluding the southernmost tip of the state. Its rapid growth rate allows it to turn vast areas of prairie into tallow forests in less than a decade once it has been established.
It can thrive in a wide range of conditions, from wet to moderately dry, and can even tolerate salt water environments. It is recognizable by milky sap, small yellow flowers, heart-shaped leaves that turn bright yellow in the fall, and a profusion of white, popcorn-shaped waxy fruit. Hence, the nickname for this tree is popcorn tree. Seeds are plentiful and dispersed by water, birds and other animals.
Since reaching Category 1 status on the invasive exotic species list in 1991, efforts have increased to control Chinese tallow’s spread throughout the state.
Category I plants are considered as the most aggressive and invasive of species and are capable of displacing native vegetation and disrupting natural ecosystems. Control has been especially difficult where the tree is used for horticultural purposes. It can be difficult to convince homeowners that the beautiful fruiting trees they had grown to love are a menace. However, it isn’t hard to convince land stewards and managers of the problem, and control and restoration efforts are well underway on many public and private lands.
As with any exotic species, prevention is the key. Remove any seedlings before they mature enough to produce seeds. Land managers can use a foliar application of 20 percent triclopyr mixed with oil-based diluents. The best time for this application is in autumn, before the tree releases its seed crop. If the tree can be mechanically cut down, spray the cut stump with the same mixture. Homeowners may be able to spray a 50 percent glyphosate solution (Roundup or equivalent) on cut stumps immediately after the tree is cut down. Be watchful of any new seedlings thereafter. Remember to always follow manufacturers’ safety labels and wear personal protective equipment when using herbicides.
Alicia Campanella has studied environmental science and participated in a month-long reforestation project in the Amazon, after which she volunteered with the Florida Park Service. She became a park ranger and worked at Fakahatchee Strand for a few years, specializing in exotic species management. She is now finishing her degree in Environmental Science and primarily spends her time studying and writing.