Dieffenbachias are native to tropical America, where some 30 species grow. They were introduced into Europe in the mid-19th century; to England and Belgium first, and then their cultivation rapidly spread to other countries. They are named in honour of J. Dieffenbach (1796-), head gardener of the Botanical Gardens in Vienna. They are distributed from Mexico and the Antilles to Peru. Many species readily interbreed. All have stout uprightthat become woody and are thickly covered with long, sheath-like stalks that embrace the . The blades are usually ovate with a prominent midrib and are decoratively patterned with blotches, marbling or stripes. They are greatly prized as houseplants for their ornamental foliage.
The inflorescence is not very conspicuous – a spadix with a relatively narrow spathe. D. picta has largewith stalks about 10-20 cm (4-8 in) long and blades 15-30 cm (6-12 inch) long and 10-15 cm (4-6 in) wide. They are usually yellow-green, with relatively few, dark green blotches that merge to form a dark band on the margin. The yellow often fades to white.
It is not difficult to grow. It requires warm conditions, and can be grown equally well in a heatedand indoors at normal room temperature. It does not tolerate direct sunlight, preferring partial shade. However, it does need adequate light for healthy growth and colourful leaves. It does not have a distinct period of rest but should be limited during the cooler months from November to February. It requires a minimum winter temperature of 16°C (60° F). In summer, water liberally and do not allow the to become too dry. Feed weekly during the growing period. Like all Dieffenbachias, this one is readily propagated by stem or tip which may be taken at any time of the year. Because they are and can cause painful, ugly swellings on the hands, the plants must be cut back with great care.
maculata (syn. D. picta)
This species , from Brazil, is one of the most widely grown.
Its stout stem can reach a height of more than 1 m (39 in). Theblades, broadly elliptic with a heart-shaped base and a pointed tip, are patterned with irregular white blotches. The spathe and spadix are greenish. It is extremely variable and includes several geographic varieties. Moreover, horticulturists have developed numerous cultivars that are difficult to distinguish from one another, and that often resemble cultivated varieties of the closely related species D. seguina. Probably the most familiar cultivar of D. maculata is ‘Julius Roehrs’; the juvenile form has yellow-green leaves and only the midribs and margins are coloured green. It was developed in the USA in 1936 and its large-scale cultivation started some 11 years later.
This has large, obovate leaves coloured dark green with yellowish or cream-white blotches, rather like stripes between the secondary veins. The cultivar ‘Mariana’ differs from the type by having leaves with large, pale patches that are white rather than yellowish. Quite often, even the midrib is not green but a pale colour. Growing requirements are the same as for other Dieffenbachias.