Culture
Winter hardy to USDA Zones 10-12. Best container growth typically occurs in a well-drained potting medium containing one part potting soil, two parts peat moss and one part sharp sand or perlite. Soils should receive consistent but moderate moisture. Plants will tolerate dry, slightly under-watered conditions, but soils should not be allowed to dry out or become overly moist. Reduce watering from late winter to spring. Fertilize plants monthly during the growing season, but reduce fertilization during fall and winter.
Growing season for this cactus is March/April to September. Full sun during the growing season for container plants brought outdoors will result in bleached foliage. Ideal temperatures for the growing season are 70-80°F. In September, steps need to be taken to regulate both temperature and light exposure in order to promote good flower bud production.
Indoor plants. In order for indoor plants to flower well during the Christmas season, it is best to provide the following as of mid-September: (a) bright daytime light, (b) night temperatures between 55 and 65°F, and (c) long nights consisting of 13 hours of total darkness (i.e., cover plant with a black cloth or place plant in a totally dark room from 6 pm to 7 am each day for 6-8 weeks). If indoor temperatures at night can be kept at 45-55°F (which admittedly can be difficult to do in a home), buds will usually form in autumn without employing the strict 13 hour darkness regimen.
Outdoor plants. For plants grown outdoors during the growing season, mid-September nighttime temperatures in the 50-55°F range usually will induce production of flower buds prior to the point where the plant is brought indoors for winter. Otherwise, the temperature and darkness requirements recommended for indoor plants should be employed.
Propagate by cuttings or grafting. Plant stem segments in small pots; water moderately during mid-summer and fertilize lightly each month.
Noteworthy Characteristics
Schlumbergera × buckleyi, commonly called Christmas cactus, is a hybrid, flat-stemmed, frost-intolerant, winter-flowering, epiphytic perennial cactus that is typically grown indoors as a container plant for enjoyment of its colorful flowers which bloom during and after the Christmas season.
Flat, jointed, leafless, green stem segments (phylloclades) sprawl downward over the container edges in pendant chains. Each stem segment (to 2 1/2” long and 3/4” wide) has rounded marginal notches. Bright magenta red to pink flowers (to 3” long) are borne at the stem ends during the period of December to February. Fruits if present are red berries.
Genus name honors Frederick Schlumberger, Belgian horticulturist.
Specific epithet honors William Buckley who created this hybrid at the Rollisson Nurseries in England around 1850 by crossing two southeastern Brazilian species (S. truncate and S. russelliana).
Problems
Flower buds may drop in autumn if plants are subjected to temperatures in excess of 90°F, large temperature fluctuations, improper watering, or sudden variations caused by changes in the room environment or by moving the plant to a different location. Root rot may occur if soils are kept overly moist. Potential insect problems include mealybugs, soft brown scale, red spider mites and aphids.
Uses
In tropical areas, this plant can be grown outside year round as an epiphyte or in a rock garden. In cooler climates, it is typically grown in hanging baskets or large pots. It is sold primarily around the Christmas season as a gift item.