Japanese Pagoda Tree (Sophora japonica)
| Summary Data | ||
|---|---|---|
| Species | Size | Basic Requirements |
| Japanese Pagoda Tree (Sophora japonica) | At 30 years height is 25 to 30’. Mature height 60’ with a spread of 60’. Annual growth rate is 12 to 18 inches. Creamy white flowers in mid to late summer | Zones 4b through 7 (8); prefers sunny open location; moist well drained acidic soil, tolerates city conditions, heat, and drought. |
The Japanese Pagoda Tree is a good tree for midsummer flowers displaying its clusters of creamy-white pea-like flowers during the heat of summer when few other trees are in bloom. Also known as the Chinese Scholar Tree, this tree is native to China, Korea, and Vietnam, but curiously is not native to Japan. .The Pagoda Tree is a legume, a member of the pea family. Consequently it is able to manufacture nitrogen from the soil on its own making it a good candidate for planting in sites with poor soils. The tree has done well in restricted root space and in urban sites.
This is a medium to large sized tree growing to 60 feet tall and wide with a broad round crown in its youth becoming more spreading with age. In the early years it grows quite rapidly, slowing down some as it approaches middle age. Like the Chinquapin Oak, this plant is relatively small in stature after thirty years of growth (maybe 25-35 feet). As such it is considered a good choice for planting under powerlines or telephone lines in a city or suburban setting.
Japanese Pagoda trees cast an attractive light dappled shade in youth, but a much more dense shade with maturity. The leaves offer a somewhat fernlike appearance having 6 to 10 inch compound leaves each with 9 to 13 small leaflets. The tree holds its green leaves well into November. Twigs of this tree remain green to provide winter color, but may be damaged during severe winters or rapid temperature fluctuations.
The creamy-white to yellowish-green large pea-like flowers in long hanging clusters blanket the tree anytime from early August to early September, with about a three week bloom period. Young seedling Pagoda trees, especially in the northern areas of its range, may not flower for the first ten or so years of its life, but in southern areas with warm summer nights, this liability tends to be non-existent. However all of this is rendered irrelevant if one uses the cultivar 'Regent', which flowers anywhere in its zone at a young age
The flowers turn into thick green pods that mature into yellow-green fruits, with the large beans appearing as knobs within the otherwise thin pods. They hang profusely from the tree and at times weight down the thin stems. Ripening in October and November and persisting into December or beyond, the seeds are readily devoured by the birds. Unfortunately there is also a resultant litter underneath the tree of the fruits or their digested residue which need periodic cleaning up especially if the tree is planted near walks or driveways.
Japanese Pagoda Tree Choices
Sophora japonica 'Regent' - the cultivar of choice, selected for its even more rapid growth rate, relatively straight central leader, earliness to flower (at about 5 years old), and glossy dark green foliage. S. davidii is a medium- to large-sized, deciduous shrub that has grayish-downy branches, which will eventually be equipped with spines. The leaves consist of 7 to 10 leaflets and in early summer clusters of small, bluish-white flowers are borne. S. tetraptera, known as the New Zealand Sophora and Kowhai, is an evergreen large shrub or small tree that can reach a height of 20 feet. This tree is only hardy in mild climates. The branches of the Kowhai are spreading and drooping and are clothed with a yellowish down when young. In late spring, pendant clusters of tubular, bright yellow, 2-inch flowers are produced; these are followed by seedpods that look like rows of beads. Its leaves consist of 10 to 20 leaflets. Princeton Upright TM has a compact, upright branching habit that makes the tree a suitable choice as a street tree.