Schlumbergera x buckleyi
Schlumbergera × buckleyi is the classic Christmas cactus, a hybrid between S. truncata and S. russelliana that has been grown as a winter-flowering houseplant for well over a century. It is distinguished from its better-known parent by its softly rounded, scalloped stem segments and its pendant, symmetrical magenta-pink flowers, which typically open a little later in the season — around midwinter — giving it the "true" Christmas cactus name. It belongs to the genus Schlumbergera, a group of epiphytic, forest-dwelling cacti native to the coastal mountains of southeastern Brazil.
Description
Schlumbergera × buckleyi grows as a much-branched, arching plant made up of flattened, leaf-like stem segments (cladodes) joined end to end. The margins of each segment are gently rounded and scalloped rather than sharply toothed — the key feature separating it from Schlumbergera truncata, whose segments carry pointed, claw-like teeth. As the plant matures the older stems arch and cascade, making it a natural subject for a hanging pot or a raised shelf.
The flowers hang downward and are more or less radially symmetrical, in shades of rich magenta and pink, with the tiered, rocket-like form typical of the genus. Blooms are produced from the tips of the segments in response to shortening days and cooler nights, usually opening around midwinter. Like all Schlumbergera, it is a short-day plant whose flowering is triggered by long, uninterrupted nights.
Cultivation
Care follows the parent genus; see Schlumbergera for full detail. Unlike desert cacti, these are epiphytes from humid, shaded Brazilian forests, so they appreciate a more forgiving regime: bright, indirect light, an open but moisture-retentive mix with plenty of bark or other coarse organic matter, and regular watering during active growth, easing off as the plant rests. They are not desert plants and should never be baked or left bone-dry for long stretches.
To set buds reliably, give the plant cool nights and long, dark nights through autumn — around six weeks of uninterrupted darkness each night, away from artificial light, is the traditional trigger. Once flower buds have formed, avoid moving or rotating the plant, as sudden changes in light, temperature or watering commonly cause the buds to drop. A summer spell outdoors in shade, followed by cool autumn nights, suits it well.
Repot only every few years, when the plant becomes crowded; see Repotting. Old, well-grown specimens can live for decades and are often passed down within families.
Propagation
Propagation is easy and is normally done from cuttings; see Propagation — cuttings. Twist or snip off a short length of two or three segments, let the cut end callus for a day or two, then insert it into a lightly moist, open mix. Cuttings root readily in warm conditions and quickly build into new plants, which is why heirloom Christmas cacti are so often shared between growers. Weak or unusual forms are sometimes grafted onto a sturdier rootstock to create a "standard" or tree form, though this is done for display rather than necessity.
Common problems
- Bud drop — the most frequent complaint; usually caused by moving the plant, draughts, or a sudden change in light or watering once buds have set.
- Failure to flower — nearly always down to too much light at night or too little cool, short-day conditioning in autumn.
- Rot — from a waterlogged, airless mix or standing water; the plant softens and segments drop.
- Pests — mealybugs (white fluff in the segment joints) and, in dry indoor air, the occasional spider mite. See Pests and diseases.
See also
- Schlumbergera — the genus overview
- Schlumbergera truncata — the Thanksgiving cactus and principal parent
- Propagation — cuttings · Soil and potting mix · Watering · Repotting