Japanese Pagoda Tree Styphnolobium japonicum

The Japanese pagoda tree is a showy, medium to large, deciduous flowering tree that is a member of the Fabaceae or pea/legume/bean family. It has a rounded crown and grows to a height of 50 to 75 feet and is equally as wide. It is grown for its attractive green foliage and fragrant summer flowers. The flowers are white, pea-like, and hang in 12-inch-long panicles. Pods appear in the fall and persist through the winter months. Its showy leaves remain green on the tree late into the fall, thereby shortening the length of time for its yellow fall color.  

The Japanese pagoda tree is native to China and was previously known as Sophora japonica and may still be seen by that name in commerce. This tree may be found growing in abundance in thickets and upland forests along rocky mountain slopes in its native habitat. 

The previous genus name, Sophora, is an Arabic name. The epithet, japonicum, means "of Japan;" however, this tree is said to be a native to China. The common name Japanese pagoda tree is the result of its being planted on the grounds surrounding Buddhist temples in Japan.  

This tree prefers full sun and loamy soils. It produces flowers in light shade and withstands heat, air pollution, and drought. It can take up to 10 years before a sapling will flower. Normally 30-40 years are needed for its best flowering.  This heat-loving specimen will flower at its showiest after experiencing a hot summer.  

The bark is grayish-brown with reddish-brown furrows as it ages. The stems remain green for 3 to 4 years before changing to brown. The leaves are alternate, compound, and have 7 to 17 leaflets. The showy, fragrant flowers appear on 12-inch long by 12-inch-wide panicles. They are showy both blooming on the tree and when they drop, as you have a showy blanket of white on the ground. The seed pods form after flowering is complete and appear like "beads on a string.". The seeds are reportedly toxic and should not be ingested.

The Japanese pagoda tree is a good urban, street, park, or lawn tree. When grown in the open, it tends to branch low to the ground.  However, with proper care, it can be formed to grow into a tall specimen with an erect trunk.

Caution: The pagoda tree has been identified as an emerging invasive threat in the mid-Atlantic region.

Seasons of Interest:

Bark:  Winter      Bloom:  Summer          Foliage:  Spring, Summer, and Fall          Fruit:  Fall and Winter

Quick ID Hints:

• deciduous 35 to 50 foot tall and as wide
• stems remain green for the first 4 year
• leaves are alternate, pinnately compound with 7 to 17 leaflets
• each leaf is ovate to lanceolate, green on the upper surface and glaucous below
• the petiole is swollen at the base and encloses the black bud
• creamy-white pea-like flowers appear in large clusters in July and August
• the fruit is a smooth, bright green pod that transitions to yellow-brown and is constricted between the seeds to give it a "beads on a string or a string of pearls" appearance

Insects, Diseases, and Other Plant Problems:  Although there are no serious insect or disease issues, leaf hoppers can be a problem.  Rust, powdery mildew, blight, canker, and verticillium wilt can affect the tree. The wood is weak and is vulnerable to strong winds or weather. It may break from the weight of snow if it is not pruned properly.

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University