Hippeastrum x hortorum
The genus Hippeastrum is found only in tropical America where it grows in mountains, savannas and periodically dry forests. According to various authorities the number of species ranges from 40 to 70. The total number must be far greater, however, for the genus is widely distributed in the Andes where many localities are inaccessible. Professor Vargas of Cuzco, Peru, has a specialized herbarium of this genus which includes species only recently discovered. For example, the species described as H. machu’picchense with huge, white, bell-likemarked with deep pink stripes on each petal was discovered unexpectedly in the seventies, even though it is indigenous to Machu Picchu, a locality visited by tens of thousands of tourists. It was found growing beside the railway track. What discoveries await us in the future cannot even be guessed at.
The only type species found commonly in cultivation is H. reticulatum striatifolium from southern Brazil. The leaves are up to 50 cm (20 in) long, with a longitudinal white stripe along the midrib. The flowers, which appear in late summer, are large, pink and very fragrant.
Modern hybrids, which often have very large, conspicuous flowers up to 30 cm (1 ft) across, are derived chiefly from crossings between H. leopoldii and H. vittatum, though other species doubtless also figured in the.
Two important factors in the cultivation of these plants are good, generous feeding during the growing season, and a period of complete rest in late summer and early autumn. In general, they need cool conditions, particularly during the flowering period, for otherwise the flowers fade quickly. In summer the plants should be put in a sunny window, in small pots of rich compost such as John Innes potting compost No. 2, watered adequately and supplied with liquid feed once a week. In late summer water should be withheld and the bulbs allowed to ‘bake’ in the autumn sun. In winter they should be put, together with the pot, in a cool place; they may also be left in darkness.