Description
Eucommia ulmoides is a deciduous tree that grows up to 20 m tall, with a trunk up to 50 cm dbh (diameter at breast height). Leaves are alternate, simple, 5 to 15 cm long and 2.5 to 7 cm wide, on a petiole 1 to 2.5 cm long. The leaf blade is elliptic to ovate, pinnately veined, rounded at the base and tapering at the tip. The bark is grayish brown and rough. Eucommia ulmoides is dioecious, meaning male and female flowers are on separate trees. Flowers are borne at the base of the leaves from March to May; the male flowers are clustered, consisting only of stamens with long anthers about 1 cm long. Female flowers are solitary, consisting mostly of an ovary about 1 cm long. The fruit is a winged seed (termed a samara), elliptic in outline and 2.5 to 3.5 cm long and 1 to 1.3 cm wide. The tip is shortly divided into two points where the stigma was; the seed is in the middle of the fruit (Wu et al. 2003).
Eucommia ulmoides is the only species in its family. A unique characteristic of this species is that the leaves contain latex; when torn, the latex solidifies into strands that hold the torn leaf together (Wu et al. 2003).
Uses
Note: Please see the disclaimer regarding any information about medical or edible uses.
Eucommia ulmoides has been cultivated in China for about 2,000 years for traditional medicine (Rivers 2018). The bark, leaves, and male flowers are used for a variety of ailments, but commonly hypertension, lower back pain, and arthritis. In Korea, the leaves have been used to treat diabetes. The efficacy of these treatments in the context of evidence-based medicine is still under research (He et al. 2014). The wood is sometimes used for furniture and fuel, and the rubber can apparently line pipes, cables, and teeth (Wu et al. 2003), although not on a commercial scale (MBG).
Eucommia ulmoides is sometimes grown as a shade tree or street tree. It prefers moist but not too wet, well-drained soils in full sun or light shade. It grows in USDA zones 4 to 7 (MBG).
Distribution
Eucommia ulmoides is found in a variety of habitats, including forests, ridges, valleys, and fields, at altitudes between 100 and 2000 m (Wu et al. 2003). It is widely distributed but scattered and rather rare; it is native to the Chinese provinces of Zhejiang, Jiangxi, Henan, Hubei, Hunan, Guizhou, Yunnan, Sichuan, Shaanxi, Shanxi, and Gansu (Rivers 2018). It is also introduced into Anhui and Beijing (Wu et al. 2003); South Korea, Vietnam, Tajikistan, Georgia, Azerbaijan, Bulgaria (Hassler 2022), and locally naturalized in Indiana, Ohio, and New York in the United States (FNAEC 2016).
Status
Eucommia ulmoides is listed on the IUCN Red List as “Vulnerable”, mostly because of deforestation throughout its range, and over-exploitation for traditional medicine. It is rare throughout its range, but has been cultivated for thousands of years, making it somewhat difficult to tell whether populations are truly wild (Rivers 2018).
References
FNAEC (Flora of North America Editorial Committee), editor. 2016. <i>Flora of North America, north of Mexico. Volume 12: Magnoliophyta: Vitaceae to Garryaceae</i>. New York: Oxford University Press.<br><br>Hassler, M. 2022. World Plants. Synonymic Checklist and Distribution of the World Flora. Version 14.0; last update 2022 August 2. [accessed 2022 Aug 26]. <a>www.worldplants.de</a><br><br>He, X., Wang, J., Li, M., Hao, D., Yang, Y., Zhang, C., He, R., and Tao, R. 2014. <i>Eucommia ulmoides</i> Oliv.: Ethnopharmacology, phytochemistry and pharmacology of an important traditional Chinese medicine. <i>Journal of Ethnopharmacology</i>, 151: 78–92.<br><br>MBG (Missouri Botanical Garden), Eucommia ulmoides. <i>Plant Finder</i>. [accessed 2022 Aug 26]. <a>http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a864</a><br><br>Rivers, M. C. 2018. <i>Eucommia ulmoides</i>. <i>The IUCN Red List of Threatened Species</i>. <a>https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T31280A130694949.en</a>.<br><br>Wu, Z. Y., Raven, P. H., and Hong, D. Y., eds. 2003. <i>Flora of China. Vol. 9 (Pittosporaceae through Connaraceae)</i>. Beijing: Science Press, and St. Louis: Missouri Botanical Garden Press.
