The plants known as epiphyllum hybrids, epiphyllums, epicacti or just epis, widely grown for their flowers, are artificial hybrids of species within the group of cacti placed in the tribe Hylocereeae, particularly species of Disocactus, Pseudorhipsalis and Selenicereus. In spite of the common name, species in the genus Epiphyllum are less often involved as parents of epiphyllum hybrids.
The parent species from which epiphyllum hybrids were bred are different in appearance and habit from most cacti. They are found in the tropical forests of Central America where they grow as climbers or on trees as epiphytes. They have leafless (or apparently leafless) flattened stems which act as the plant's photosynthetic organs. Relatively large flowers are borne on the sides of the stems; in many species they open at night.
Hybrids between Disocactus and Epiphyllum have been called ×Disophyllum or ×Aporophyllum. The Epiphyllum Society of America (the International Registration Authority for hybrids of the Tribe Hylocereeae) maintains a list of epiphyllum hybrids (and Hylocereeae species) which contained over 7,000 names in 1996.
Epiphyllum hybrids need different treatment from semi-desert cacti. They should be protected from direct sunlight, with preferably 75% shading at midday. They are not frost hardy, so need to be protected from freezing conditions. It is recommended that the growing medium allows rapid drainage of water and is open, with at least one third of coarse material to prevent compaction. Plants should be kept moist. High nitrogen fertilisers are not recommended; no fertiliser should be given during the winter rest period.
Propagating epiphyllum hybrids from cuttings is easy. Rooting hormone can be applied to the base of the cutting before it is allowed to dry for ten days or more so that the cut forms a callus. The cutting is then planted sufficiently deeply so that it can stand upright. Water is not given for two weeks, after which the growing medium is kept at least slightly moist. Plants can be misted. They are fast growing plants and should flower within two years. Epiphyllum hybrids should be re-potted every 2 to 3 years as they tend to deplete the nutrients in their growing medium.
We have about half dozen different Epiphyllum hybrids growing in pots and they do quite well outside in Melbourne's climate. All of them we have grown from cuttings, and I am not aware of their "official" name. This pink one is quite spectacular with blooms about 20 cm in diameter. They last a few days (up to seven) on the plant and they can even be cut at the base of the stem as a cut flower that lasts 4-5 days indoors.
This post is part of the Floral Friday Fotos meme.