These are much larger plants than the foregoing and the flowers they produce are much larger and more showy. The plants offered for sale are hybrids between the various species, in particular Epiphyllum ackermannii, which comes from Mexico, Central America and South America. The natural flowering time of the epiphyllum is early summer; consequently you will probably purchase a plant at this time. After flowering the plant is best kept in a shady spot, in a good light. At the end of the summer bring the plant indoors or into the greenhouse. Water normally from the flowering period until the end of autumn, and then withhold water to give the plants a resting period, until the first signs of the flower buds, which should be some time in early spring. Do not allow the compost to dry out completely, but water very sparingly and keep it well on the dry side. During this resting period the plants should be kept in a cool atmosphere, at about 4 5 - 5 0 ° F ( 7 - 10°C). As soon as pot is full of roots. Use the smallest size of pot compatible with the root system and only transfer to a larger pot when necessary.
The propagation of epiphyllums is by cuttings, because like the Christmas cactus it takes four to eight years for plants to flower when grown from seed. Select a healthy terminal growth of the leaf-like stems and remove the top 5 - 6 in (13-15 cm), making a the flower buds are visible put the plants in a warmer temperature, minimum 6 0 ° F (15°C), and commence watering again. Feed every two weeks with a high potash fertiliser until the first flowers open. Repotting, if necessary, should be carried out shortly after the plants have finished flowering, using soilless compost of the type suitable for ericaceous plants, because epiphyllums require an acid compost free from lime. Do not repot plants before they are pot-bound, as an epiphyllum flowers best when its clean cut with a knife. Allow the cutting to dry off for two or three days and then push the cut end into moist peat, % in (13 mm) deep, and support it with a thin stake. Cover the pot with a plastic dome or enclose in a plastic bag for two or three weeks and keep in a minimum temperature of 6 0 ° F (15°C) until it is well rooted when it should be potted in the compost in a 2'/2-in (6-cm) or 3-in (9-cm) pot. The growth of epiphyllums is much more erect than the Christmas cactus and plants should be kept staked from the time of taking the cutting, to encourage the plant to remain erect; otherwise it tends to sprawl, owing to the weight of the young stems. Plants can be grown on for years. The flowers of epiphyllums are usually shades of red, but there are also hybrids with flowers in white, pink, cream and purple or mauve.
If you grow epiphyllums in the house, on a windowledge, it is advisable to avoid moving them once the flower buds have formed, because the buds are drawn towards the light. If a plant is turned the buds will obviously have to change direction and this weakens them to the extent that you get quite a number of buds dropping off the plant. This does not apply in the greenhouse because there is sufficient light all round the plant. Once all the buds have opened into flowers the plant can be moved without detriment. The same remarks apply to the Christmas cactus and the Easter cactus.
