pronounced: rad-er-MAK-ee-uh SY-nick-uh
pronounced: steh-ree-oh-SPUR-mum SY-nick-um
Radermachera is named for the amateur Dutch botanist J.C.M. Radermacher (1741-1763), an officer of the Dutch East India Company, who worked in Batavia. Sinicus is botanical Latin for ‘of China’. In the synonym, Stereospermum is from the Greek στερεος (stereos), firm, solid, and σπερμα (sperma), a seed.
This is an evergreen tree native to the subtropical mountain regions of southern China and Taiwan. In its natural state it can reach heights of up to 30 m, with a trunk diameter of a metre. The plants illustrated here are of a dwarf variety, ‘Summerscent’. There are several dwarf varieties available, and they are often grown as indoor plants, though they seldom flower indoors, and are grown for their attractive leaves. They are a relatively large plant for indoors, easily reaching a height of 1.5 m or even more, but they can be cut back if size is a problem. Indoors, avoid direct sunlight that could burn the leaves. The soil should be kept slightly moist, if possible using lime-free water. The plant likes high humidity levels, so it is best to mist the foliage regularly. These are not plants for a house in which the residents smoke – they much dislike cigarette smoke! They should also be shielded from draughts. These plants should not be re-potted – they do best when root-bound. They do not like change – leaf drop will follow any change in their circumstances. If leaf drop does occur, the stalks should be cut back by two-thirds to a half.
The tree form has bipinnate leaves, 20 – 70 cm long and 15 – 25 cm wide, divided into numerous small glossy green leaflets 2.5 – 7 cm long, narrowly ovate or elliptic-ovate in shape.
The flowers are white, trumpet-like, with crinkly petals, and are about 7 cm long, shaped rather like a large Bignonia flower. They occur in panicles at the leaf axils or at the ends of branches. The flowers are followed by rather insignificant-looking fruits in slender capsules.
Propagation may be by taking cuttings, but these can be difficult to strike. The plants can also be grown from seed, and, as they require light for germination, the seeds should not be covered.
In parts of Sydney, the plant has escaped from gardens and has possibly become naturalized.
