Begonia x corallina ‘Lucerna’
The subtropical and tropical regions of Africa, America and Asia are the home of some 1,000 species of begonias, which grow at sea level in lowlands up to elevations of 4,000 m (13,500 ft). The large majority grow in deep shade, in the undergrowth of the tropical rain forests or on shaded wet rocks. This, of course, does not rule out exceptions. Begonia veitchii grows in Peru at elevations of more than 3,000 (10,000 ft) in crevices on sunny rocks the same as B. michoacanensis from Mexico; the latter furthermore requires heavy, compacted laterite. In general it may be said that begonias, particularly the cultivated forms, are shade-loving plants and require an acidic compost that is permanently and adequately moist.
Begonia x corallina ‘Lucerna’ is living proof that the old tried and tested hybrids should not be forgotten. It was raised in the early 19th century by crossing either B. corallina and B. ‘Madame Char-rat’ or B. corallina and B. teuscheri. It reaches a height of 2 m (6 ft), is nicely branched, and in ideal conditions the leaf blade may be up to 35 cm (14 in) long. The large, drooping, coral-red malewhich last for a long time, make a magnificent display.
Begonia is suitable for indoor plant-cases and also for demijohns. Particularly good are the small and rare species such as Begonia paulensis, B. rajah, B. imperialis ‘Smaragdina’, B. acida, and B. ma-soniana ‘Iron Cross’.
Cultivation is not difficult. The growing medium should consist of peat with an addition of sand, enriched by a little compost, or John Innes potting compost No. 1.
Propagation is also simple — by stem cuttings or leaves. Insert the leaf stalks in a peat and sand mixture where they will root rapidly; even a piece of leaf blade containing some of the main veins can be used — place it on the surface of the same mixture in a warm and moist environment.