Six Rivers “Dirty Dozen” Invasive Species
Chinese Tallow (popcorn tree) (Triadica sebifera)
Define Invasive Species: must have all of the following –
- Is non-native to the area, in our case northwest Florida
- Introduced by humans, whether intentional or accidental
- Causing either an environmental or economic problem, possibly both
Define “Dirty Dozen” Species:
These are species that are well established within the CISMA and are considered, by members of the CISMA, to be one of the top 12 worst problems in our area.
Chinese tallow is from eastern Asia.
In China, the plant is cultivated for the production of seed oil. It was first introduced to the United States intentionally in the 1700s as an ornamental plant. It was later used in the production of soap. It is now well established throughout the southeast and spreads very quickly to disturbed areas.
EDDMapS currently list 21,924 records of this plant. All but 10 are listed in the southeastern U.S. There are records in the midwest and in California.
Within our CISMA there are 2084 records. This is CERTAINLY underreported.
Chinese tallow (the popcorn tree) grows to about a height of 20 feet, but there are some trees growing much taller. The leaves are ovate in shape, smooth margins with a sharp spear-like tip. They are arranged alternately on the branches. The flowers are tiny and emerge from a spike-like structure. They are very popular with bees and other insects. The fruit are produced in clusters of three lobed structures. These seed pods are dark in color, but the white fruit emerges in the fall giving it’s other common name – popcorn tree. The bark of the tree is a light gray color and bark segments are small and outlined in black.
Issues and Impacts:
Currently, the issue and impacts have been debated. The plant is an aggressive spreader, quickly taking over newly disturbed areas and reducing the occurrence of several native plants. Such areas as clearing for new development, agriculture, and prescribed burning of forest lands have all had to battle infestations of this tree. One stormwater drain in the Pensacola area is a complete tallow forest. The plant spreads quickly by seed dispersal from fruit eating birds and cut stumps are known to generate numerous new plants from the underground root system.
Once established the tallow can become a monoculture that is known to be toxic to some livestock and can cause nausea/vomiting in humans. Again, there is the reduction of native plants.
The other side of the story involves its popularity as a pollen plant for beekeepers, and sometimes used – at risk – by cattle for shade in the heat of the summer.
Despite the current debate, Chinese tallow is listed as a Category I invasive plant and a Florida noxious weed.
Management of this plant can be hard once established. Removing small saplings as they emerge by hand is a good start.
Mowing or burning small trees has been shown to be effective and burning larger trees has worked as well. If burning is not an option, then cutting the tree down as low to the ground as possible, then applying a herbicide to the stump can work. However, cutting alone will not solve the problem.
Herbicide of choice is triclopyr. This can be applied to the leaves directly, but it is recommended this be done in late summer just before the plant goes to seed. If applying to the bark, or a cut stump, it can be applied any time of year. If spraying on the bark, begin at ground level and spray up to 15 inches of the stump. If you have cut the tree, apply to the cut stump immediately after cutting.
The U.S. Department of Agriculture (USDA) is currently working with two possible biological controls. One is a small beetle (Bikasha collaris) that is known to consume the leaves and stems of the plant. The other is the caterpillar of the moth (Gadirtha fusca) who feeds on the leaves. In order for the USDA to release such biological controls they must go through an intensive series of tests to make sure they do not become a problem in themselves. As of the time of this writing (2021) they have completed their trials and the process of releasing is open for public comment until Feb 22, 2021.
For more information on this Dirty Dozen species, contact your local extension office.
Chinese Tallow, University of Florida IFAS Center for Aquatic and Invasive Plants
Early Detection and Distribution Mapping System (EDDMapS)
Six Rivers CISMA