The Hardy rubber tree (Eucommia ulmoides) is a deciduous tree, native to China, therefore also known as the Chinese rubber tree. It is a low-branches tree with a broad spreading crown. The tree is primarily known for its shinny dark-green pointed leaves with serrated edges that have an elliptical shape like the leaves of an elm tree. The trunk bark is used int traditional Chinese medicine. E. ulmoides is the only member of the Eucommiaceae family. It is the only tree from temperate regions known to produce rubber. If the leaf is gently torn apart and held upside-down by its stalk, the two separate parts remain hanging together connected almost invisibly by a network of gossamer like latex fibers. The tree was introduced to the West in 1896 from plants propagated in China; in China the bark is used for medicinal purposes. The genus name comes from the Greek, eu, meaning “good” and kommi, meaning “gum” for the rubber produced by this tree. Ulmoides refers to the “ulm-like” leaf and samara.
Common name: Chinese Rubber Tree; Hardy Rubber Tree; Gutta Percha Tree
Scientific Name (family and order): Eucommia ulmoides Oliver (Eucommiaceae, Garrales, Lamids)
Species Origin: S.W. China
New Jersey Status: USDA
Habit: Broad spreading tree; 65’ high; Dense oval crown, low branches.
Habitat: Zone 4 -7.
Trunk/Stem: Bark dove-gray, deeply fissured.
Leaves: Deciduous, Simple, Alternate. The leaves are spirally arranged on petiolate leaves without stipules. Ovate to elliptical with leathery sharply tapered (acuminate) pointed tip 8” long by 3 ½ ‘ wide; the margins are serrate; top leaf is glossy dark green with prominent pinnate venation. The base is obliquely rounded.
Flowers: Dioecious. Inflorescences are axillary clusters. Male and female flowers very small, without a perianth (sepals or petals) and unisexual opening on the old shoots on separate plants in late spring just before or as the young leaves are emerging. Males flowers may have up to twelve stamens on short linear filaments. Female flowers have a stalked ovary composed of two fused carpels forming a single locule with two reflexed and spreading sigmas. Wind pollinated
Fruits and seeds: The fruits are long-elliptic compressed samaras (like-ash samaras but with apical notch) with wing around the margin (winged fruit), 1 ½’ long in clusters each samara containing a single seed.