Common
Name: Japanese Pagoda TreeScientific Name: Sophora japonica
Family: Leguminosae or Legume Family
This Tree in Colorado:
Native to northern China and Korea. Long planted in Japan, and also grows in Europe and North America. Good specimens at the CSU Pueblo campus in southeast Colorado. The Pagoda tolerates a wide range of moisture and atmospheric conditions if the soil is fair to good. This tree does not tolerate extremely poor soils.
Growth Rate, Form and Size:
Moderate grower on most sites at first, then slower. Leaves are broadly ovate, with upward spreading branches, medium-fine texture. 40 to 50 feet tall with a 40 to 50 foot spread. Likes sun exposure.
Landscape Value:
Where soils are fair, it will tolerate drought. Useful as a specimen tree or along streets, it provides light shade and tolerates urban stresses – smoke, heat, pollutants.
Zones:
Hardiness Zones 5 to 8.
Flowers:
Cream colored, pea-like, 1 ½ inches in diameter, in loose clusters 10-12 inches long. Flowers in summer. Male and female in the same flower. Moderately showy. 3 to 7 per cluster. Flowering usually occurs after age 10.
Fruit:
A yellow-green-brown pod in clusters, 2-4 inches long, containing numerous seeds, constricted between each seed. Clusters persist into fall.
Foliage:
Alternate, compound; 6 to 10 inches long, composed of 7 to 17 ovate leaflets that are 1 to 2 inches long with smooth margins. Leaves are rounded at the base and taper to a point at the tip. Medium to dark green above and only slightly lighter green below. Little to some yellow fall color.
Bark:
Young stem is green and moderately slender. Young branches remain dark, shiny green for several years before finally becoming a medium to dark brown. Bark on a mature tree is shallowly furrowed and medium brown. Wood is moderately strong and appears to be sufficiently flexible (so wind or ice damage is minimal).
Limitations:
Young trees are somewhat difficult to train in upright growth. Shedding of leaves, flowers, and fruit parts at different times causes litter problems. The flowers stain sidewalks. The species is susceptible to twig blight, canker, mildew, leaf hoppers, and scale insects, however usually these are not serious. Severe cold can predispose trees to Nectria canker. Leaves and seeds may have a mildly toxic property.
Notes:
Also known as Chinese scholar tree.
Cultivars:
Selections have been made for improved growth habit, glossy foliage, and blooming at an earlier age.
Information Sources:
Whitcomb, Carl E. “Know It & Grow It III – A Guide to the Identification and Use of Landscape Plants”. 1996.
Gerhold, Lacasse, Wandell, editors. ‘Street Tree Fact Sheets’. A publication of the Municipa Tree Restoration Program, with support of the USDA Forest Service, NE Area State & Private Forestry. 1993.