Koelreuteria paniculata Laxm.

A deciduous tree up to 30 to 60 ft high, with soft, pithy wood and rather gaunt habit when young, becoming more compact with age; young shoots minutely downy. Leaves alternate, pinnate, sometimes partially bipinnate; the nine to fifteen leaflets ovate, short-stalked or stalkless, coarsely and irregularly toothed, downy beneath. The whole leaf is from 6 to 18 in., or even more, in length, and the separate leaflets from 1 to 4 in. long, the larger ones often pinnately lobed at the base. Flowers in a large, terminal pyramidal panicle, sometimes over 12 in. long, made up of a series of elongated, slender racemes, carrying numerous short-stalked, yellow flowers, each about 1⁄2 in. wide; petals four; sepals ovate or ovate-oblong, acute; stamens eight, downy. Fruit a conical, inflated, three-valved capsule, 11⁄2 to 2 in. long; valves acute or acuminate. Seeds about the size of peas, dark brown.

Native of China; introduced to England in 1763, and said to have first been cultivated at Croome, in Worcestershire. It is quite hardy and very handsome, flowering in July and August. When seen at its best the tree is a mass of deep yellow flowers, and these are succeeded by the striking bladder-like fruits. It loves the sun, and I have never seen it quite so fine in this country as it is in central France. Its handsome leaves turn bright yellow in autumn. It likes a good loamy soil. The seeds afford the best means of propagation, and are sometimes set in this country. Failing them, root-cuttings may be used. The tree is probably not long-lived, and is rather subject to the attacks of coral-spot fungus.

There are several specimens at Kew, none of great age, 30 to 40 ft in height and 13⁄4 to 4 ft in girth. An example near the Pinetum, planted 1934, measures 40 × 23⁄4 ft. Others recorded are: Syon House, London, 45 × 3 ft (1967); Oxford Botanic Garden, 49 × 31⁄2 ft (1970); Hergest Croft, Heref., 40 × 31⁄2 ft (1961); Victoria Gardens, Bath, 30 × 5 ft (1962).

From the Supplement (Vol. V)

specimens: Kew, pl. 1914, 46 × 31⁄4 ft (1981), pl. 1934, 46 × 31⁄2 ft (1976), pl. 1932, 40 × 31⁄4 ft (1980); Chelsea Physic Garden, London, 36 × 8 ft (1984); Syon Park, London, 52 × 41⁄2 ft (1982); Battersea Park, London, 38 × 41⁄4 ft (1983); Savill Garden, Windsor Great Park, 30 × 23⁄4 ft (1976); Burford House, Surrey, 52 × 51⁄2 + 5 ft (1978); Battle Abbey, Hastings, Sussex, 33 × 43⁄4 ft (1978); Alexandra Park, Hastings, 50 × 41⁄2 ft (1980); Joyce Green Memorial Hospital, Dartford, Kent, 42 × 41⁄4 ft (1979); Oxford Botanic Garden, 46 × 33⁄4 ft (1981); University Botanic Garden, Cambridge, 33 × 3 ft (1982); Hergest Croft, Heref., 46 × 33⁄4 ft at 3 ft (1969).

[var. apiculata]. – This variety is not recognised by Meyer, its supposedly distinctive characters being part of the normal variation of the species. Older trees under this name derive from Wilson 3364, collected for Messrs Veitch in 1904. The tree at Kew planted in 1914 is one of the originals from this sending.

K. bipinnata – A synonym to be added is K. integrifolia Merrill. Seeds of K. bipinnata have been received from China under this name.

† K. elegans (Seem.) A. C. Smith – This species, in its typical state, is confined to the two main islands of Fiji, but the following subspecies occurs in east Asia:

subsp. formosana (Hayata) F.G. Meyer K. formosana Hayata; K. henryi Dummer. – An endemic of Formosa at low altitudes, allied to K. bipinnata. It was introduced to Kew in 1976 by means of seeds received from the Taiwan Forestry Institute, but is unlikely to be of any value for British gardens.