Chinese Tallow Tree in Japan: An Autumn Beauty That Seeds Itself Everywhere
In the southern United States, the Chinese tallow tree is one of the most troublesome invasive trees. In Japan, the same tree is planted along streets and in parks for its autumn colour. And then it turns up where nobody planted it.
We are a small tree care and landscape business in Mie Prefecture, central Japan. One autumn we noticed a thin young tree, about one metre tall, with leaves going from pale yellow to deep red. Nobody had planted it. It was a Chinese tallow, and a bird had almost certainly brought it.
What the Japanese name means
In Japanese the tree is called nankin-haze. Nankin is the old Japanese name for Nanjing, and it was often used for things that came from China. Haze is the Japanese wax tree (Toxicodendron succedaneum), the tree that Japan used for centuries to make plant wax for candles. So the name says "the wax tree from China".
The two trees are not related. The Japanese wax tree belongs to the sumac family and its sap gives a bad rash. The Chinese tallow (Triadica sebifera) belongs to the spurge family, the same family as poinsettia.
Why it came to Japan
According to Fukuoka Prefecture's invasive species database, the tree came to Japan from central and southern China in the Edo period (1603 to 1868) as a garden plant. It was also planted to collect wax and for its timber.
The wax is on the seeds. In autumn the dark husks split open and three white seeds appear, coated in a waxy layer. In English it is sometimes called the popcorn tree, and the name fits.
In recent decades, because the autumn colour is so beautiful, it has been planted as a street tree and in parks. From there it has escaped and gone wild.
How it spreads
The white seeds are eaten by many birds. In Japan, crows, sparrows, doves, tits and white-eyes all feed on them, and they drop the seeds wherever they fly. The young trees grow very fast and like sunny, open ground.
Fukuoka Prefecture says the tree is now spreading on riverbanks, grassland and the edges of irrigation ponds, and lists it as an invasive species that needs action. The prefecture's 1975 flora did not record it growing wild, so it probably went wild there after the 1980s.
The American story
The United States Forest Service notes that Chinese tallow was first brought to South Carolina in the 1700s. It is often said that Benjamin Franklin sent the seeds, in 1776, although that story is not certain. Oklahoma State University describes how it spreads along riverbanks, ditches and coastal wetlands, and can also grow on drier ground, crowding out native plants.
So the same tree travelled east to Japan and west to America, as an ornamental and a wax tree, and went wild in both places.
Look, but do not touch the seeds
The seeds look like popcorn and children want to pick them up. But the seed and its sap contain irritant compounds. Touching them can cause a skin rash, and eating them can cause vomiting and stomach pain. Birds eat them without trouble. People should not.
What we see in our work
In gardens we care for, a Chinese tallow seedling is a small sign that a bird has visited, and a reminder that the trees we plant along the street do not stay on the street.
When a client asks whether to keep a self-sown one, we ask two questions first. Is there space for a tree that can reach fifteen metres? And is there a river, pond or field nearby where its seeds could start a new stand?
If the answer to the second question is yes, we usually suggest a native tree with good autumn colour instead. In central Japan that can be a Japanese maple or a wild cherry.
A street tree in Japan, an invasive in the American South. The tree is the same. What changes is where its seeds land.
