Amur Corktree

Phellodendron amurense

amur_corktree.jpg

amur corktree
Jim Rathert
Other Common Name
Japanese Corktree
Family

Rutaceae (citruses or rues)

Description

Amur corktree is a medium-sized tree with a broad-spreading, rounded crown and dark green foliage.

Leaves are opposite, pinnately compound, up to 14 inches long, with 5–11 leaflets that are 4½ inches long, elliptical, with an acute tip; upper surface dark green, lower surface lighter. When bruised, leaves smell something like turpentine.

Bark, with age, becomes uniquely ridged and corky.

Flowers May–June; in erect clusters of small yellow or yellowish-green flowers, male and female flowers on separate plants.

Fruits clusters of pea-sized fleshy, round berries, green but maturing to black in October, containing 5 seeds each, persisting into winter.

Size

Height: 30 to 45 feet.

Habitat and conservation

This hardy species adapts to a wide variety of soil types, withstands heat and drought, tolerates cold, and resists pests. These characteristics make it attractive for landscaping, but please do not plant it. The qualities that make it survive well also contribute to its invasive nature. The female trees, especially, can be highly invasive.

image of Amur Corktree Distribution Map
Distribution in Missouri

Potentially statewide.

Status

Considered invasive in many states, but not yet in Missouri. It is basically free of pests and adapts to many soil conditions as well as pollution and drought. The male and female trees are easily distinguished in the fall, when female trees have clusters of black berries. Old trees with massive branches and attractive bark develop a sculptured look. It is a poor choice as a street tree, because of its spreading, low-branching habit.

Human connections

In addition to its use as a shade and landscape tree in America, this plant has a long history in traditional Chinese medicine. It has proven itself invasive in the northeastern United States and in Illinois, and has shown invasive tendencies in St. Louis.

Ecosystem connections

It's a bad deal for nature if this plant starts displacing our native trees. Oaks and hickories, for example, provide important, nutritious nuts that help wildlife survive winter, but Amur corktree provides berries sweet with sugar but with far less nutritional value. As corktrees increase, wildlife will decrease.