About Koelreuteria paniculata Laxm.
Koelreuteria paniculata Laxm. is a small to medium-sized deciduous tree that reaches 7 meters (23 feet) tall, with a broad, dome-shaped crown. Its leaves are pinnate, 15–40 cm (6–16 in) long, and occasionally reach 50 cm (20 in). Each leaf holds 7–15 leaflets that are 3–8 cm long with deeply serrated margins. Larger leaflets positioned at the middle of the leaf are sometimes pinnately divided themselves, but the leaves are never consistently fully bipinnate, unlike the related species Koelreuteria bipinnata. This tree produces yellow flowers with four petals, which grow in large terminal panicles measuring 20–40 cm (8–16 in) long. The fruit is a three-part inflated, bladder-like pod that is 3–6 cm long and 2–4 cm broad. It starts out green, and ripens to orange then pink during autumn, and holds several dark brown to black seeds 5–8 mm in diameter. Koelreuteria paniculata has been cultivated since ancient times. During the Zhou dynasty, it was one of five official memorial trees, along with Pinus tabuliformis, Platycladus orientalis, Styphnolobium japonicum and certain poplars, and was planted beside the tombs of scholars. Today it is widely grown as an ornamental tree in temperate regions across the globe, valued for the attractive appearance of its flowers, leaves and seed pods. Several cultivars have been developed specifically for garden planting: 'Fastigiata' has a narrow crown, while 'September Gold' flowers in late summer. In the United Kingdom, the cultivar 'Coral Sun' has received the Royal Horticultural Society's Award of Garden Merit. In some areas, particularly the eastern United States and especially Florida, it is classified as an invasive species.
