Amur Corktree (Phellodendron amurense) — identification, habitat & look-alikes

Amur corktree is a deciduous tree native to northeastern Asia, with gray, corky outer bark and bright yellow inner bark. In the United States it was planted as an ornamental, but seed-producing trees have escaped and become invasive in parts of the Northeast and Mid-Atlantic.

Appearance

Appearance: Older trunks have ridged, gray-brown, slightly spongy bark. A scratch through the outer bark reveals the vivid yellow inner layer.
Growth form: This deciduous tree usually reaches about 30–45 ft (9–14 m) and develops a broad crown.
Leaves: Opposite leaves are 10–15 in (25–38 cm) long. Each usually carries 5–13 leaflets and smells pungent when crushed.
Flowers: It is , with male and female flowers on separate trees. In North Carolina, small yellow-green flowers appear in May and June.
Fruit: Female trees bear clusters of green fruits that ripen black in fall and may hang into winter.

Look-alikes

Ash TreesFraxinus

Ashes also have opposite compound leaves, but their fruits are dry and winged. Female Amur corktrees bear round black fruits, and older trunks have thick corky bark with yellow inner bark.

Why they get mixed upBoth have opposite branches and leaves divided into leaflets.

Where it lives

Typical habitats: urban woodlands
riparian areas
parks
street plantings
Range: Native to northeastern Asia, this tree was planted in the United States and has escaped in states including Illinois, New York, Pennsylvania, and Virginia.
Preferred conditions: It grows best in sun and rich soil but tolerates several soil types and drought once established.

Life cycle

Seed dispersal: Birds eat the abundant fleshy fruits and carry the seeds beyond plantings.

Name and classification

About the name: Phellodendron amurense wilsonii is a variety of Amur corktree.
Varieties and forms: Named male cultivars are grown because they cannot produce the seed-bearing fruits.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed
Threats: In invaded forests, dense patches can displace native hardwood seedlings and other plants.

Culture and stories

Culture and stories: The tree was introduced to the United States in 1856 for ornamental planting.
In Minnesota, only named male cultivars may be sold.

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