Epiphyllum X hybridum: Orchid Cactus
Some cacti have become very popular, even with those who do not cultivate them otherwise, because of their showy. Heading the list, next to the widely-grown Christmas cactus, is the orchid cactus, a complex hybrid derived from crossings between the species themselves and usually also with related genera. In Europe they are generally known by the name phyllocactus. True Epiphyllum species are cacti that generally flower at night and that is why they are often hybridized with the genera Selenicereus and Nopalxochia; the resulting hybrids have flowers that often remain open for 2 days.
Epiphyllums, as their name indicates, are of epiphytic nature, generally rooting in the forks of branches, their long thin stems twining over the bark to which they hold fast by means of clinging rootlets; the leaf-like expanded shoots either hang downwards or stand away from the trunk. Seedlings often root in the humus collected in the fork of a branch by another plant and so, for example, one often comes across orchids (such as laelias) covered with these cacti or leafy cacti sharing a small bit of life-giving humus with anthuriums.
A great many hybrids in colours ranging from pure white to violet purple are cultivated nowadays. The flowers are truly huge, sometimes up to 30 cm (1 ft) in diameter. Leafy cacti may be grown as epiphytes, but then (because of the other plants) it is difficult to provide them with the necessary dry and cool conditions in winter, without which they flower poorly. It is better to grow them in the traditional way in a porous, humusy compost where they make very rapid growth.
Two of the loveliest varieties, which have become classics, are the crimson ‘Ackermannii’ and the many-flowered, soft pink ‘Deutsche Kaiserin’.