EPIPHYLLUMS

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.

EXACUM CULTIVATION TIPS

Family Gentianaceae

Sow the small seeds on the surface of a soilless seed compost and gently tap the pot to settle the seeds into the compost. Then lightly dampen the surface of the compost with a fine spray of water and cover the seed pan with a sheet of glass. Place in a temperature of 60-65°F (15-18°C) and keep covered until germination is evident, then remove the glass and place in a good light, protected from direct sunlight. When the seedlings are large enough to handle, pot in 2'/2-in (6-cm) pots, in compost E6, and finally in 4 or 4Vj-in (10 or 11.5-cm) pots, depending on the growth the plant has made.

To make steady growth the plants require a temperature of 60-65°F (15-18°C) and although seed can be sown from late winter to spring, in order to obtain flowering plants the same year it is not advisable to sow earlier than early spring, unless you are able to provide the temperature requirement. Of course, the earlier the seeds are sown, the earlier the plants will bloom and the longer the flowering period, in fact, if seed is sown in summer the plant will bloom the following summer, but you would have to maintain a minimum temperature of 50-55°F (10- 13°C) throughout the winter, and even so you would probably lose a few plants. Seed sown in early spring should produce flowering plants by the middle of summer.

When plants are in bloom, never allow the compost to become too dry, otherwise the flowers will shrivel up and die. As the flowers fade they should be removed to ensure continuity of flowering. Although exacums are perennials they should be treated as greenhouse annuals and discarded after flowering. When a good compost, such as E6, is used, it is not necessary to feed the plants during their short growing season; otherwise start feeding about eight to ten weeks after their final potting.

EXACUM / Family Gentianaceae

The species Exacum a/fine was only introduced to Europe at the beginning of the twentieth century. It was found growing on the island of Socotra, which is situated at the entrance of the Gulf of Aden. The cultivar Exacum offline 'Midget' is the variety usually offered for sale by seedsmen, and it is a more compact plant than the species, growing to about 9 in (23 cm) in height. The plants are naturally bushy, and when in flower are covered all over with small fragrant mauve or lavender-blue flowers, with a cluster of golden anthers in the centre. The flowers are saucershaped and usually 6 - 1 3 mm across. Plants are freely available and should be bought when the first flowers are beginning to open; they should then give a continuity of bloom for two or three months. However, exacums are very easy to grow from seed and if you require several plants it is more economical to grow your own.