In the wild, these cacti live on trees, as epiphytic orchids do. In the home, they are dependable, easy, long-lived houseplants. Plants are often confused with Zygocactus. The many kinds differ principally in flower color.
S. x buckleyi. CHRISTMAS CACTUS. May be labeled S. bridgesii. Old favorite to 2 ft. high, 3 ft. wide. Arching, drooping, bright green branches of flattened, scallop-edged, smooth, spineless, 112-in. joints. Can bear hundreds of many-petaled, long-tubed, 3-in.-long, rosy purplish red flowers at Christmastime. For late December bloom, give plant cool night temperatures (5055F), and about 14 hours of darkness per day during November.
S. truncata. THANKSGIVING CACTUS. Native to Brazil. To 1 ft. high and wide. Bright green, 1- to 2-in., toothed joints; two large teeth at tip of last joint on each branch. Short-tubed, 3-in.-long, scarlet flowers with spreading, pointed petals from late fall through winter. Tends to bloom earlier than S. x buckleyi, though bloom periods may overlap. Many selections are sold, with blooms in white, pink, salmon, orange, and yellow.
Plant in well-drained soil. Feed with liquid fertilizer every 7-10 days during active growth and bloom. Keep soil moist from time flower buds appear to after blooms finish. Then let soil go somewhat dry between waterings. Like poinsettias, Christmas and Thanksgiving cacti need long nights and short days to initiate floweringat least 14 hours of complete darkness per day.