Sophora

This is a group of tender and hardy, evergreen and deciduous trees and shrubs. S. japonica, the Chinese Scholar Tree or Japanese Pagoda Tree, is a native of China. This handsome, deciduous plant makes a wonderful shade tree and can even tolerate the polluted atmosphere of the city. When grown in a yard, the Japanese Pagoda Tree can reach a height ranging from 50 to 75 feet; however, when grown along the road in compact soil, it only grows to 30 or 40 feet. The 6- to 10-inch, bright-green, pinnate leaves are fern-like and consist of 9 to 15, elliptic leaflets. The leaves are extremely pest-free. This tree begins to bloom when 10 to 15 years of age. In late summer and early fall, 10- to15-inch panicles of small, white, pea-shaped flowers are produced at the ends of branches. They live about a month and are followed by yellow pods, which persist well into the winter. A variety of S. japonica, Regent, blooms at an earlier age than the wild species - usually at 6 to 8 years; this variety has lustrous, 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.

Pot Cultivation

Sophoras should be grown in moist, well drained loam that is acidic or slightly alkaline. The soil should be deep enough to accommodate their long root systems. They flourish in full sun. Young trees may be pruned in autumn. Low branches can be removed to provide headroom under the tree.

Propagation

Seeds may be sown in deep, well-drained pans of sandy soil, in the spring. Moisten the soil and set in a warm greenhouse. When they sprout, the seedlings are potted separately in 3-inch pots and, when established in these, are placed in a cold frame to harden off. They are eventually transferred to larger pots and the following spring, into a nursery border. Cuttings can be made in the spring from young shoots. They are inserted in sand in a warm greenhouse. When they've formed roots, they are potted and treated as seedlings. Trees of the weeping kind, S. japonica pendula, are obtained by grafting shoots of the pendulous kinds onto stocks of S. japonica.